Coolant cooled type semiconductor device

ABSTRACT

A coolant cooled type semiconductor device capable of achieving a superior heat radiation capability is provided, while having a simple structure. While a plurality of semiconductor modules are arranged in such a manner that main surface directions of these semiconductor modules are positioned in parallel to each other in a interval along a thickness direction thereof. These semiconductor modules are sandwiched by coolant tube having folded portions with fixing members. As a consequence, both surfaces of the semiconductor module can be cooled by a single coolant tube with a uniform pinching force.

This is a Continuation of application Ser. No. 10/756,340 filed Jan. 14,2004, Ser. No. 10/3 14,139 filed Dec. 9, 2002, now U.S. Pat. No.6,845,012 and patent application Ser. No. 09/837,382 filed Apr. 19, 2001which issued as U.S. Pat. No. 6,542,365 B2 issued Apr. 1, 2003. Theentire disclosure of the prior applications is hereby incorporated byreference herein in its entirety.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of Japanese PatentApplications No. 2000-118093 filed on Apr. 19, 2000, No. 2000-136434filed on May 10, 2000, No. 2000-172091 filed on Jun. 8, 2000, No.2000-195887 filed on Jun. 29, 2000, No. 2000-200021 filed on Jun. 30,2000, and No. 2000-353257 filed on Nov. 20, 2000, the contents of whichare incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a coolant cooled type semiconductor device.

2. Description of the Related Arts

To improve cooling characteristics of semiconductor modules that containsemiconductor chips having terminals, it has been proposed that watercooling type cooling members are made in contact with semiconductormodules so as to cool these semiconductor modules. Also, JapaneseLaid-open Patent Application No. Hei-6-291223 has proposed adouble-sided heat-radiating type semiconductor module in which heat isradiated from both surfaces of this semiconductor module.

However, in the above-described conventional water-cooling typesemiconductor modules, a cooling member must be joined to thesemiconductor modules, while maintaining superior heat transfercharacteristics. To realize such superior heat transfer characteristics,there is the best way such that an electrode (also having heat transferfunction) that is exposed from the main surfaces of the semiconductormodules is joined to the cooling member by a soldering material.

If the cooling member is a cooling unit through which water or coolantpasses, the cooling unit may be connected to either a refrigeratingcycle apparatus or a cooling water circulating apparatus. Therefore, theabove-explained electrode member of the semiconductor module and thecooling member is set to a predetermined potential (normally, groundpotential) equal to that of the refrigerating cycle apparatus, or thecooling water circulating apparatus.

However, when such an electrically insulating spacer is employed, sincethe electrode member of the semiconductor module cannot be joined to thecooling member, the electrode member of the semiconductor module andalso the cooling member must be strongly pressed against theelectrically insulating spacer under such a condition that uniformpinching pressure is given to the respective face portions in order toreduce the thermal resistance between the electrode member of thesemiconductor module and the cooling member.

The above-described construction in which both the semiconductor moduleand the cooling member are strongly pressed against the insulatingspacer under uniform pinching pressure would induce the complex entirestructure. Also, the pinching force can not be controlled easily. Inother words, when the pinching force is low, the thermal resistancebetween the semiconductor module and the cooling member is increased, sothat the cooling capability is lowered. To the contrary, when thepinching force is excessively high, the semiconductor chips built in thesemiconductor module are broken.

Also, in order to cool double-sided of a large number of thesesemiconductor chips, or double-sided cooling type semiconductor cardmodules, a large number of the above-explained cooling members arebranched, resulting in complex structures and increased manufacturecost. These increase the risk that fluids may be leaked due to anincreased total number of joint places of the coolant distributiontubes.

SUMMARY OF THE INVENTION

The present invention has been made to solve the above-explainedproblem, and therefore, has an object to provide a coolant cooled typesemiconductor device having a simple structure and also capable ofrealizing a superior heat radiation capability, and further capable ofreducing a possibility of fluid leakages.

According to a first aspect of the present invention, a semiconductordevice is disposed between a first cooling member and a second coolingmember, a first insulating member is disposed between the first coolingmember and the semiconductor device a second insulating member isdisposed between the second cooling member and the semiconductor device.In this way, the semiconductor is insulated from the first and thesecond cooling member while heat generated in the semiconductor deviceradiates through the cooling members.

According to a second aspect of the present invention, a cooled typesemiconductor device comprises: first and second cooling members,through which a coolant flows, pinching a semiconductor devicetherebetween tightly by a fixing member.

It is preferable that a cooling unit has a flat shape and has a firstportion corresponding to the first cooling member, a second portioncorresponding to the second cooling member, and a folded portionconnecting the first and second portions.

According to a third aspect of the present invention, a cooled typesemiconductor device comprises: a first semiconductor chip having a highside semiconductor switching element which has a first positive and afirst negative electrodes, a second semiconductor chip having a low sidesemiconductor switching element which has a second positive and a secondnegative electrodes, wherein the first negative electrode and the secondpositive electrode are connected to a common mid terminal, the firstpositive electrode is connected to a high potential terminal and thesecond negative electrode is connected to a low potential terminal whoseelectric potential is lower than that of the high potential terminal.

According to a fourth aspect of the present invention, a cooled typesemiconductor module comprising: a first heat radiating plate disposedon a main surface of the module and a second heat radiating platedisposed on a back surface of the module, wherein a heat sink contactsthe first radiating plate, and a biasing-holding member connected withthe heat sink presses the semiconductor module to the heat sink.

BRIEF DESCRIPTION OF THE DRAWINGS

Other objects and features of the present invention will become morereadily apparent from a better understanding of the preferredembodiments described below with reference to the following drawings, inwhich;

FIG. 1 is a cross-sectional view showing a coolant cooled typesemiconductor device of a first embodiment;

FIG. 2 is a plane view for indicating this semiconductor device whoselid is taken out;

FIG. 3 is a cross-sectional view of this semiconductor device shown inFIG. 2;

FIG. 4 is a plan view for indicating a coolant indirect cooling typesemiconductor device of another embodiment;

FIG. 5 is a cross-sectional view for indicating the coolant indirectcooling type semiconductor device shown in FIG. 4.

FIG. 6 is a side view for indicating a leaf spring member shown in FIG.5.

FIG. 7 is a plane view for indicating this semiconductor device whoselid is taken out;

FIG. 8 is a cross sectional view for representing this semiconductordevice of FIG. 7;

FIG. 9 is a plan view for indicating this semiconductor device whose lidis taken out;

FIG. 10 is a cross-sectional view for representing this semiconductordevice of FIG. 9;

FIG. 11 is a plan view for indicating this semiconductor device, fromwhich a lid thereof is taken out;

FIG. 12 is a cross-sectional view for representing this semiconductordevice of FIG. 11;

FIG. 13 is a side view for indicating a leaf spring member shown in FIG.12;

FIG. 14 is a transversal sectional view of a main portion of thesemiconductor device of FIG. 7;

FIG. 15 is a cross-sectional view taken along an arrow XV—XV of FIG. 14;

FIG. 16 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of the third embodiment;

FIG. 17 is a cross-sectional view taken along an arrow XVII—XVII of FIG.16;

FIG. 18 is a transversal sectional view of a main portion showing amodified mode of a sixth embodiment;

FIG. 19 is a cross-sectional view taken along an arrow XIX—XIX of FIG.18;

FIG. 20 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a seventh embodiment;

FIG. 21 is a longitudinal sectional view of the main portion of FIG. 20;

FIG. 22 is a side view of a flat cooling tube of FIG. 20;

FIG. 23 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a eighth embodiment;

FIG. 24 is a longitudinal sectional view of the main portion of FIG. 23;

FIG. 25 is a side view of a flat cooling tube of FIG. 23;

FIG. 26 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a ninth embodiment;

FIG. 27 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a tenth embodiment;

FIG. 28 is a cross-section view taken along an arrow XXVIII—XXVIII ofFIG. 27;

FIG. 29 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a eleventh embodiment;

FIG. 30 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a twelfth embodiment;

FIG. 31 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a thirteenth embodiment;

FIG. 32 is a transversal sectional view of a main portion showing amodified mode of the eleventh embodiment;

FIG. 33 is a transversal sectional view of a main portion showing amodified mode of the twelfth embodiment;

FIG. 34 is a transversal sectional view of a main portion showing amodified mode of the thirteenth embodiment;

FIG. 35A is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a fourteenth embodiment;

FIG. 35B is a completion view of the coolant cooled type semiconductordevice;

FIG. 36 is a transversal sectional view showing a main portion of acoolant cooled type semiconductor device of a fifteenth embodiment;

FIG. 37 is a cross-sectional view taken along an arrow XXXVII—XXXVII ofFIG. 36;

FIG. 38 is a sectional view for showing a semiconductor switching modulealong a thickness direction thereof;

FIG. 39 is a sectional view for a semiconductor device having thesemiconductor switching module in FIG. 38;

FIG. 40 is an exploded diagram for indicating the semiconductorswitching module of FIG. 38;

FIG. 41 is an oblique perspective figure for indicating thesemiconductor switching module of FIG. 38;

FIG. 42 is an oblique perspective figure for modification of thesemiconductor switching module of FIG. 41;

FIG. 43 is a plan view for indicating a major portion of thissemiconductor device;

FIG. 44 is a circuit diagram of a three-phase inverter circuit device;

FIG. 45A is an exploded perspective view of a semiconductor module shownin FIG. 44;

FIG. 45B is a perspective view of the semiconductor module shown in FIG.44;

FIG. 46 is a perspective view of the semiconductor module shown in FIG.44;

FIG. 47 is a plan view of a main portion of the inverter circuit deviceshown in FIG. 44;

FIG. 48 is a side view of the inverter circuit device shown in FIG. 47;

FIG. 49 is a side view showing a pinching structure of the semiconductormodule shown in FIG. 44;

FIG. 50 is a side view showing a pinching structure of the semiconductormodule in a twentieth embodiment;

FIG. 51 is a side view showing a pinching structure of the semiconductormodule in a twenty-first embodiment;

FIG. 52 is a side view showing a pinching structure of the semiconductormodule in a twenty-third embodiment;

FIG. 53 is a side view showing a pinching structure of the semiconductormodule in a twenty-fourth embodiment of the present invention;

FIG. 54 is a side view showing a pinching structure of the semiconductormodule in a twenty-fifth;

FIG. 55 is a side view showing one portion of a pinching structure ofthe semiconductor module in a twenty-sixth embodiment;

FIG. 56 is a plan view of a main portion of an inverter circuit deviceof a twenty-seventh embodiment;

FIG. 57 is a side view of the inverter circuit device shown in FIG. 56;

FIG. 58 is a side view showing a pinching structure of the semiconductormodule shown in FIG. 56;

FIG. 59 is a side view showing a modified mode of FIG. 58.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(First Embodiment)

Referring now to drawings, a description will be made of a coolantcooled type semiconductor device according to first preferred embodimentof the present invention.

FIG. 1 is a sectional view showing a substantial part of this coolantcooled type semiconductor device along a thickness direction thereof

[Structure of Semiconductor Module]

The cooled type semiconductor module 1 has a coolant tube 2 and spacers3 made of a metal or having a thermal transfer characteristic. Morespecially, the semiconductor module 1 has a semiconductor chip 101 a inwhich an IGBT element is formed, a semiconductor chip 101 b in which aflywheel diode is formed, a metal heat transfer plate 102 working as aheat sink as well as an electrode (namely, emitter side in thisembodiment), and a metal heat transfer plate 103 working as a heat sinkas well as an electrode (namely, collector side in this embodiment)likewise. Reference numeral 104 denotes soldering layers. A metal heattransfer plate 102 has projecting portions 102 a projecting on sides ofthe semiconductor chips 101 a and 101 b thereof, and a projectingterminal portion 102 b. A metallic heat transfer plate 103 has aprojecting terminal portion 103 b. A control electrode terminal 105 isconnected to a gate electrode of the IGBT through a bonding wire 108.Insulating plates 8 are disposed on both sides of the semiconductormodule 1. A sealing resin portion 19 seals the semiconductor chips 101 aand 101 b.

Both the semiconductor chips 101 a and 101 b are joined to a mainsurface (major surface) provided on an inner side of the metal heattransfer plate 103 by the soldering layer 104, and the projectingportions 102 a of the metal heat transfer plate 102 are joined to mainsurfaces of the semiconductor chips 101 a and 101 b by the solderinglayer 104 at an opposite side of the metal heat transfer plate 103. As aresult, an anode electrode and a cathode electrode of the flywheel diodeare connected to a collector electrode and an emitter electrode of theIGBT in a so-called “back-to-back connection” manner. For instance, Moand W are employed for the metal heat transfer plates 102 and 103. Thesoldering layers 104 may be replaced with other joint functionmaterials.

The two projecting portions 102 a have a difference in thicknesses whichare capable of absorbing a difference in thickness between thesemiconductor chip 101 a and the semiconductor chip 101 b, so that anouter major surface of the metal heat transfer plate 102 constitutes aflat plane.

The sealing resin portion 19 is made of, for example, an epoxy resin,and is molded to cover side surfaces of these metal heat transfer plates102 and 103. As a result, both the semiconductor chips 101 a and 101 bare molded by the sealing resin portion 19. It should be understood thatthe outer main surfaces, namely contact heat receiving surfaces of themetal heat transfer plates 102 and 103 are completely exposed.

The projecting terminal portions 102 b and 103 b are provided to projectfrom the sealing resin portion 19 in the right direction as viewed inFIG. 1. Plural control electrode terminals 105 so-called “lead frameterminals” are connected to the gate (control) electrode of thesemiconductor chip 101 a where the IGBT is formed.

In this embodiment, each of the insulating plates 8 corresponding to aninsulating spacer is composed of an aluminum nitride film, butalternatively other insulating films may be adopted. The insulatingplates 8 closely contact the metal heat transfer plates 102 and 103,while completely covering these heat metal transfer plates 102 and 103.Alternatively, the insulating plates 8 may be simply made in contactwith both the metal heat transfer plates 102 and 103, or a heat transfermaterial such as silicone grease may be coated thereto. The insulatingplates 8 can be joined to these metal heat transfer plates 102 and 103by various methods. Further, each of the insulating plates 8 may closelycontact the side of the coolant tube 2.

The coolant tube 2 is manufactured in such a manner that an aluminumalloy is manufactured by either an extract-molding method or anextrude-molding method to form a plate member, and this plate member iscut off at a necessary length. As shown in FIG. 1, a sectional area ofthe coolant tube 2, as viewed along a thickness direction thereof, has alarge number of flow paths 22 which are partitioned by a large number ofpartition walls 21. These partition walls 21 extend at a given intervalin a flow path direction.

In accordance with this structure, the pinching pressure applied to therespective portions on the contact heat-receiving surface 20 of thecoolant tube 2 can be made constant.

In this embodiment, each of the spacers (namely, soft material member) 3is made of a soft metal plate such as a soldering alloy. Alternatively,the spacer 3 may be made of a film that is coated on a contact plane ofthe coolant tube 2. The surface of this soft-material spacer 3 can beeasily deformed by receiving pressure (will be explained later), and thedeformed spacer 3 can be easily fitted to very fine concave/convexportions and cambers of the insulating material 8, and also to verysmall concave/convex portions and cambers of the coolant tube 2 so thatthermal resistance can be reduced by closely contacting. Optionally,grease having a thermal transfer characteristic may be coated onsurfaces of the spacer 3. Of course this spacer 3 may be omitted.

[Structure of the Semiconductor Device]

Referring now to FIG. 2 and FIG. 3, a description will be made on anexample of a coolant cooled type semiconductor device with employment ofthe above-explained double-sided heat-radiating type semiconductormodule. FIG. 2 is a plane view for indicating this semiconductor devicewhose lid is taken out. FIG. 3 is a cross-sectional view of thissemiconductor device shown in FIG. 2.

In the drawings, reference numeral 1 shows semiconductor modules,reference numeral 2 indicates the coolant tube, reference numeral 4denotes a case whose one end is opened, and reference numeral 5 denotessmoothing capacitors. Also, reference numeral 6 denotes supportingplates, reference numeral 7 denotes through bolts, reference numeral 10shows nuts, reference numeral 11 denotes a lid, reference numeral 23denotes a coolant distribution tube on an inlet side, reference numeral24 is a coolant distribution tube on an outlet side, reference numeral27 shows a nut used to fix the coolant distribution tube. Referencenumeral 23 a shows a tip portion of the coolant distribution tube 23.

The coolant flat tube 2 is folded (bent) to have a winding shape and isdisposed inside the case 4. In this embodiment, the coolant tube 2 isfolded three times so as to have three spaces. These three spaces areisolated from each other by three folded portions 2 a, 2 b and 2 c.Three pairs of contact heat receiving planes 20, 20 of the coolant tube2 are disposed in each space respectively and are arranged along anup-and-down direction in FIG. 2. Each pair of the contact heat receivingplanes 20, 20 extends to a right/left (lateral) direction in FIG. 2, sothat each pair of the contact heat receiving planes 20, 20 is disposedparallel to the other pairs as viewed in this drawing. These contactheat receiving planes 20, 20 are made flat, and are located opposite andparallel to each other. Reference numerals 2 a, 2 b, and 2 c representcurved (folded) portions of the coolant tube 2.

One pair of the three pairs of the contact heat receiving planes 20 and20 that is located at a lower position in FIG. 2, namely the flatportions of the both sides of the curved portion 2 a of the coolant tube2 are closely contacted to both surfaces of the three double-sidedheat-radiating type semiconductor modules 1 through a spacer 3 (notshown in FIG. 2 and FIG. 3), so that the semiconductor modules 1 canradiate heat generated therein from both sides thereof which closelycontact the contact heat receiving planes 20, 20. These threedouble-sided heat-radiating type semiconductor module 1 will constitutean upper arm (high side) of a 3-phase inverter circuit which drives aload such as a motor.

Another one pair of the three pairs of the contact heat receiving planes20 and 20 that is located at an upper position in FIG. 2, namely theflat portions of the both sides of the curved portion 2 c of the coolanttube 2 are closely contacted to both surfaces of the three double-sidedheat-radiating type semiconductor modules 1 through a spacer 3 (notshown in FIG. 2 and FIG. 3), so that the semiconductor modules 1 canradiate heat generated therein from both sides thereof which closelycontact the contact heat receiving planes 20, 20. These threedouble-sided heat-radiating type semiconductor module 1 will constitutea lower arm (low side) of a 3-phase inverter circuit.

The remaining pair of the three pairs of contact heat receiving planes20, 20 that are located at a center position, namely the flat portionsof the both sides of the curved portion 2 b of the coolant tube 2 areclosely contacted to the outer surface of two smoothing capacitors 5.

Each of these semiconductor switching elements is arranged in such amanner that one flywheel diode has a back-to-back connection to one IGBTelement, as explained in the above embodiment.

The smoothing capacitors 5 are connected between a positive DC powersupply and a negative DC power supply of the above-explained 3-phaseinverter circuit. These smoothing capacitors 5 are employed so as toprevent a switching noise from entering to the DC power supplies througha power supply line.

As previously described, both the surfaces of the respectivedouble-sided heat-radiating type semiconductor modules 1 are closelycontacted the contact heat receiving planes 20 of the coolant tubes 2.Moreover, pinching plates 6 abut against the flat planes of the coolanttubes 2 and 2 provided on the lower and upper outermost sides. Thethrough bolts 7 pass through both the upper end portions and the lowerend portions of both the pinching plates 6 and 6 along a stackingdirection, i.e., the up and down direction in FIG. 2, and are fastenedby nuts 10.

The fastening force of the nuts 10 is adjusted in such a manner that thepressure applied to the semiconductor modules 1 by the coolant tubes 2becomes a predetennined value. In other words, the clamp constituted bythe pinching plate 6, the through bolt 7, and the nut 10 sets thepinching force applied to the semiconductor module 1 by the coolanttubes 2 and also serves as a structural member capable of supporting the3-phase inverter circuit apparatus.

As shown in FIG. 3, one end of the coolant tube 2 is joined to an inletof a coolant distribution tube 23, and the other end of the coolant tube2 is joined to an outlet coolant distribution tube 25. Both a tip endportion 23 a of the coolant distribution tube 23 and a tip end portion(not shown) of the coolant distribution tube 25 are projected from thebottom portion of the case 4 downwardly. A screw (thread) is formed onthis tip end portion 23 a, and this screw may be coupled to a coolantdistribution tube of an externally provided refrigerating cycleapparatus (not shown). It should be understood that this coolant tube 2may constitute a portion of an evaporator of this refrigerating cycleapparatus, or the entire portion thereof. Reference numeral 27 shows anut which fastens/fixes the coolant distribution tubes 23 and 25 onto abottom portion of the case 4.

In accordance with this structure, since the coolant tubes 2 can bedetachably coupled to the external cooling mechanism (heat radiationapparatus) outside the case, even when the fluids (coolant) are leakedfrom these coupling portions (above-mentioned tip end portions), it ispossible to avoid such an adverse influence caused by the short-circuitoccurred in the circuit. Also, the apparatus can be partially replaced.

In accordance with this embodiment, since both the arms of the 3-phaseinverter circuit are cooled by the same coolant which flows along theboth of arms, fluctuations in the heat radiation capabilities betweenthese arms can be reduced.

Also, a difference in cooling capabilities among the respectivedouble-sided heat-radiating type semiconductor modules 1 disposed in thesame arm can be reduced.

Furthermore, each of the double-sided heat-radiating type semiconductormodules 1 is pressured by a common pressuring member, i.e., the foldedcoolant tube 2, so that pinching force per unit area as well as pinchingareas, which is applied between each of the semiconductor modules 1 andthe coolant tube 2, is made substantially equal to each other.

As a result, a difference in the pinching force of the coolant tubes 2with respect to the semiconductor modules 1 can be reduced. In otherwords, all of the semiconductor modules 1 are applied a substantialuniform pinching force with the folded coolant tube 2.

After all, while the difference in the cooling capabilities among therespective semiconductor modules 1 is made small, such a compactsemiconductor device having a superior cooling characteristic can berealized.

Also, while the smoothing capacitor 5 may also be cooled under bettercondition, in such a case that the double-sided heat-radiating typesemiconductor module 1 radiates very large heat under a transient state,this smoothing capacitor 5 can absorb heat through the coolant tubes 2,thereby functioning as a heat sink.

(Modification)

Even when the above-explained semiconductor module 1 of the embodimentis replaced by a semiconductor chip, a similar operation and effect maybe achieved.

[Second Embodiment]

FIG. 4 and FIG. 5 show a coolant cooled type semiconductor deviceaccording to another embodiment of the present invention. FIG. 4 is aplan view for indicating this semiconductor device from which a lidthereof is taken out. FIG. 5 is a cross-sectional view for representingthis semiconductor device of FIG. 4.

(Structure of Semiconductor Device)

In this semiconductor device of this embodiment, while the semiconductormodule 1, the coolant tube 2, the smoothing capacitor 5, and thepinching plate 6 are made in the same array as that of the embodiment 1,this above-mentioned component set is sandwiched by three sets of leafspring members 9. This leaf spring member 9, as shown in FIG. 6, isconstituted by one piece of center leaf portion 90 b, and one pair ofplate-shaped both edge portions 90 a and 90 a. The center leaf portion90 b is arranged parallel to a bottom portion of the case 4. One pair ofboth edge portions 90 a and 90 a are elongated from the respective bothedge portions of this center leaf portion 90 b at a right angle,respectively, and also are located opposite to each other. Referencenumeral 91 shows a groove portion which is formed in the center leafportion 90 b of a large-sized spring member 90.

In accordance with this embodiment, the respective members can beassembled in a simpler manner. In addition, pinching forces applied tothe respective members do not have so much fluctuation in each other. Inother words, the constant pinching force can be obtained in a simplemanner, and also either the semiconductor chip or the double-sidedheat-radiating type semiconductor module can be detachably mounted in avery simple manner, so that the replacement workability can beconsiderably improved.

[Third Embodiment]

Referring now to FIG. 7 and FIG. 8, a description will be made of anexample of a coolant cooled type semiconductor device with employment ofa dual-plane heat-radiating type semiconductor module. FIG. 7 is a planeview for indicating this semiconductor device whose lid is taken out.FIG. 8 is a cross sectional view for representing this semiconductordevice of FIG. 7.

Reference numeral 1 shows a semiconductor module, reference numeral 2Aindicates a coolant tube, reference numeral 4 denotes a case whose oneend is opened, and reference numeral 5 represents one pair of smoothingcapacitors which are connected in parallel to each other. Also,reference numeral 6 denotes a pinching plate, reference numeral 9 showsa leaf spring member, reference numeral 11 indicates a lid, referencenumeral 43 denotes an inlet header, reference numeral 44 is an outletheader, and reference numerals 25 and 26 show coolant distributiontubes, and reference numeral 27 snows a nut used to fix the coolantdistribution tubes.

The coolant distribution tubes 25 and 26 are fixed on a bottom portionof the case 4 by using nuts. Tip portions of the coolant distributiontubes 25 and 26 penetrate the bottom portion of the case 4 to beprojected along the downward direction.

Both the coolant distribution tubes 25 and 26 are communicated to loweredges of the inlet header 43 and the outlet header 44 in an integralform within the case 4. Both the inlet header 43 and the outlet header44 own hollow plane shape. The headers 43 and 44 are stood on the bottomsurface of the case 4 at a right angle within the case 4, and arepositioned opposite to each other in a parallel manner with an interval.Six pairs of coolant tubes 2 are arranged among main counter surfaces ofboth the inlet header 43 and the outlet header 44.

The respective coolant tubes 2 are arranged in parallel to each other onthe main surfaces of both the inlet and outlet headers 43 and 44 at theright angle. Both edges of these coolant tubes 2 are separatelycommunicated and joined to both the inlet and outlet headers 43 and 44.As will be explained later, each of these coolant tubes 2 owns a hollowthick-plate shape.

The coolant tubes 2 in each pair pinches the double-sided heat radiatingtype semiconductor module 1. Six pieces of semiconductor modules 1 whichconstitute a 3-phase inverter circuit are sandwiched by different pairsof coolant tubes 2 and 2.

The pinching plates 6 made of metal flat plates are closely contacted toouter-sided main surfaces of such coolant tubes 2 and 2 which sandwichthe semiconductor module 1. One set of these pinching plate 6, coolanttube 2 semiconductor module 1, coolant tube 2, and pinching plate 6 arepressed by the leaf spring member 9. The pinching plate 6 may alsofunction as a heat sink. The leaf spring member 9 has an U-shaped formmade of a spring rigid plate. This plate spring member 9 sandwiches theabove-explained set between both edge portions of this plate springmember 9 under certain pressure. It should also be noted that while thepinching plate 6 is omitted, one pair of coolant tubes 2 and 2, thesemiconductor module 1, and the coolant tube 2 may be directlysandwich-pressured by this leaf spring member 6.

The smoothing capacitor 5 owns a compressed shape, and a flat outersurface of this smoothing capacitor 5 is closely contacted to a rearmain surface of the header 44.

Each of the semiconductor modules 1 constitutes each of semiconductorswitching elements of the 3-phase inverter circuit. Each of thesesemiconductor switching elements is arranged in such a manner that oneflywheel diode is cross-coupled to one IGBT element. One of the pairedsemiconductor modules 1 and 1 constitutes a high-sided semiconductormodule of a single-phase inverter circuit, whereas the other module ofthe paired semiconductor modules 1 and 1 constitutes a low-sidedsemiconductor module of the same single-phase inverter circuit. As aconsequence, 3 pairs of these semiconductor modules 1 and 1 constitute asingle-phase inverter circuit for a U-phase, a single-phase invertercircuit for a V-phase, and a single-phase inverter circuit for aW-phase, respectively. The smoothing capacitor 5 corresponds to such asmoothing capacitor which is connected between a positive DC powersupply and a negative DC power supply of the above-explained 3-phaseinverter circuit. This smoothing capacitor 5 is employed so as tosuppress switching noise.

The coolants having the same flow rates and the same temperatures aresupplied through the inlet header 43 to the respective coolant tubes 2.Furthermore, since these coolant tubes are sandwich-pressured by acommon sandwich-pressuring member, sandwich-pressure force per unitarea, which is applied between each of the semiconductor modules 1 andthe coolant tube 2 is made substantially equal to each other, and alsothe sandwich-pressure areas are made equal to each other. As a result,the sandwich-pressure force of the coolant tubes 2 with respect to thesemiconductor modules 1 is made substantially equal to each other. As aresult, the cooling capabilities of the respective semiconductor modules1 can be made substantially equal to each other.

[Fourth Embodiment]

FIG. 9 and FIG. 10 show a coolant cooled type semiconductor device.

(Structure of Semiconductor Device)

FIG. 9 is a plan view for indicating this semiconductor device whose lidis taken out. FIG. 10 is a cross-sectional view for representing thissemiconductor device of FIG. 9.

In the drawings, reference numeral 7 indicates a through bolt, referencenumeral 10 represents a nut.

Different features between the semiconductor device in the thirdembodiment and the semiconductor device in the fourth embodiment will bemainly explained below.

Six pairs of compressed coolant tubes 2A are separately provided with ainterval along a thickness direction thereof. Among each pair of thesecoolant tubes 2A and 2A, one pair of semiconductor modules 1 and 1 aresandwiched along a vertical direction of FIG. 9.

As previously explained in FIG. 7, both surfaces of each phase of thesemiconductor modules 1 and 1 are sandwiched by the coolant tubes 2A and2A, while the smoothing capacitors 5 having the compressed cylindricalshapes are also sandwiched between the coolant tubes 2A and 2A as shownin FIG. 9. In other words, Five spaces are disposed among the coolanttubes 2A, one pair of the semiconductor modules and the smoothingcapacitor 5 is disposed alternately in each space. Moreover, thepinching plates 6 abut against the coolant tubes 2A and 2A provided onthe right and left outermost sides. The through bolts 7 pass throughboth the upper end portions and the lower end portions of both thepinching plates 6 and 6 along the stacking direction, and are fastenedby the nuts 10.

The fastening force of the nut 10 is adjusted in such a manner that thesandwich-pressure force applied to the semiconductor module 1 exerted bythe coolant tubes 2A and 2A becomes a predetermined value. In otherwords, such a sandwich-pressuring member constituted by the pinchingplate 6, the through bolt 7, and the nut 10 may have a function capableof setting the sandwich-pressure force applied to the semiconductormodule 1 exerted by the coolant tubes 2A and 2A, and also anotherfunction as a structural member capable of assembling/supporting the3-phase inverter circuit apparatus.

Therefore, since these coolant tubes are sandwich-pressured by a commonsandwich-pressuring member, sandwich-pressure force per unit area, whichis applied between each of the semiconductor modules 1 and the coolanttube 2 is made substantially equal to each other, and also thesandwich-pressure areas are made equal to each other as describedabove-mentioned embodiment.

(Modification)

Even when the above-explained semiconductor module 1 of the embodimentis replaced by a semiconductor chip, a similar operation effect may beachieved.

[Fifth Embodiment]

FIG. 11 and FIG. 12 show a coolant cooled type semiconductor device.

(Structure of Semiconductor Device)

FIG. 11 is a plan view for indicating this semiconductor device, fromwhich a lid thereof is taken out, and FIG. 12 is a cross-sectional viewfor representing this semiconductor device of FIG. 11.

In this semiconductor device of this embodiment, while a set of thesemiconductor module 1, the coolant tube 2A, the smoothing capacitor 5,and the pinching plate 6 are made in the same array as that of thefourth embodiment, this component set is sandwiched by a large-sizedleaf spring member 90 in a batch mode.

This large-sized leaf spring member 90 is made by enlarging the leafspring member 9 as explained in the third embodiment. The large-sizedleaf spring member 90 is constituted by one piece of center leaf portion90 b, and one pair of plate-shaped both edge portions 90 a and 90 a. Thecenter leaf portion 90 b is arranged at an attitude parallel to thebottom portion of the case 4. One pair of both edge portions 90 a and 90a are elongated from the respective both edge portions of this centerleaf portion 90 b at a right angle, respectively, and also are locatedopposite to each other. Reference numeral 91 shows a groove portionwhich is formed in the center leaf portion 90 b of the large-sizedspring member 90 as shown in FIG. 13.

In accordance with this embodiment, the respective members can beassembled in a simpler manner, and the pinching force having a smallfluctuation can be applied to the respective members.

Moreover, since one piece of the pinching structure (large-sized springmember 90) can apply the pinching force equal to each coolant tube 2A,semiconductor module (semiconductor chips), and smoothing capacitor 5,such a large current control semiconductor device having a compact andsimple pinching construction can be realized.

(Modifications of Detail Construction of Cooling System)

A connecting structure of the headers 43, 44 and the flat cooling tube2A shown in FIG. 7, for example, will next be explained with referenceto FIGS. 14 and 15. FIG. 14 shows a transversal sectional view of a mainportion of the semiconductor device of FIG. 7. FIG. 15 shows across-sectional view taken along an arrow XV—XV of FIG. 14.

The headers 43, 44 respectively have opening portions 50, 60 fitting theflat cooling tube 2 thereinto in connecting positions of the flatcooling tube 2. The opening portions 50, 60 are surrounded by concaveportions 51, 61 having a ring shape. These ring-shaped concave portions51, 61 are respectively constructed by inside sleeve wall portions 52,62 joined to end portions of the flat cooling tube 2A, outside sleevewall portions 53, 63, and ring-shaped bottom wall portions 54, 64connecting the inside sleeve wall portions 52, 62 and the outside sleevewall portions 53, 63.

The outside sleeve wall portions 53, 63 face the inside sleeve wallportions 52, 62 at predetermined intervals, and surround the insidesleeve wall portions 52, 62 on outer sides. In FIG. 14, the concaveportions 51, 61 are formed in a U-shape biting into sides of the headers5, 6. End portions of the fiat cooling tube 2 are fitted into theseopening portions 50, 60, and are soldered to inner circumferential facesof the inside sleeve wall portions 52, 62.

Incidentally, the opening portions 50, 60 and concave portions 51, 61constitute connecting tube portions. Similar members of the headers 43and 44 described in any following embodiments also constitute theconnecting tube portions.

In accordance with this embodiment, the concave portions 51, 61 of theheaders 43, 44 can be easily elastically deformed in the thicknessdirection (also called an X-direction) of the semiconductor module 1 incomparison with the flat cooling tube 2A. Therefore, when positions ofthe flat cooling tube 2A and the semiconductor module 1 are shifted inthe above X-direction in assembly, this position shift can be absorbedby the elastic deformation.

In accordance with the coolant cooled type semiconductor device of theabove embodiment, the following effects can be obtained.

A cooling fluid (coolant) at low-temperature is uniformly distributed toeach semiconductor module 1, and dispersion of cooling effects can bereduced. Each semiconductor module 1 can radiate heat to the flatcooling tubes 2A on both sides so that the cooling effects areexcellent.

A pair of flat cooling tubes 2A and the semiconductor module 1 arenipped and pressed by the U-shaped leaf spring member 9 as a pinchingmember. Accordingly, the semiconductor module 1 can come in closecontact with the flat cooling tubes 2A by a simple structure usinguniform force in each portion so that contact heat resistance can bereduced.

The ring-shaped concave portions 51, 61 constituting flat cooling tubeconnecting portions of the headers 43, 44 surround the flat coolingtubes 2A. In addition, plate thickness of these ring-shaped concaveportions 51, 61 are set to be equal to or smaller than an averagethickness of the flat cooling tubes 2A in the X-direction so thatrigidity of the ring-shaped concave portions 51, 61 in the X-directionis set to be smaller than that of the flat cooling tubes 2A.Accordingly, when a space width between the pair of flat cooling tubes2A is smaller than a thickness of the semiconductor module 1, andpositions of the flat cooling tubes 2A and the semiconductor modules 1are misarranged, this error in size can be preferably absorbed withoutcurving the flat cooling tubes 2A in a bow shape. As a result, the flatcooling tube 2A can preferably come in contact with the above metallicheat radiating plate of the semiconductor module 2A withoutirregularities on each portion of main faces of the flat cooling tubecoming in contact with the semiconductor module.

(Modified Mode)

In the above embodiment, the flat cooling tube 2A can be displaced bythe ring-shaped concave portions 51, 61 in the X-direction. However, athin sleeve portion may be projected from each of the headers 43, 44 toan end portion of the flat cooling tube 2A, and the flat cooling tube 2Amay be also joined to this sleeve portion.

In this case, this sleeve portion can be easily elastically deformed inthe X-direction with main portions of the headers 43, 44 as startingpoints. Therefore, while the deformation of the flat cooling tube 2Aitself is restrained, the flat cooling tube 2A is displaced in theX-direction, and the flat cooling tube 2A and the semiconductor module 1can preferably come in close contact with each other.

When a thin connecting tube portion formed separately from the flatcooling tube 2A and the headers 43, 44 is interposed between the flatcooling tube 2A and the headers 43, 44, similar to the above case, thisconnecting tube portion can be preferentially elastically deformed sothat similar effects can be obtained. Further, portions of the headers43, 44 connected to the flat cooling tube 2A may be also plasticallydeformed instead of the elastic deformation. However, the elasticdeformation is advantageous since no hindrance is caused in repetitiousexchange of the semiconductor module 1, etc. Furthermore, there are alsoeffects in that force of this elastic deformation can be utilized as oneportion or all portions of force for pressing and biasing the flatcooling tube 2A against the semiconductor module 1.

[Sixth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIGS. 16 and 17. In this embodiment, theflat cooling tube 2A on an outermost side in the X-direction among theflat cooling tubes 2A in FIGS. 14 and 15 is replaced with a first highrigid flat cooling tube 45, and an (N+2)-th flat cooling tube 2A (N isan integer equal to or greater than one) from the first high rigid flatcooling tube 45 is changed to a second high rigid flat cooling tube 46.The first and second high rigid flat cooling tubes 45, 46 are fixed tothe headers 43, 44 without the ring-shaped concave portions 51, 61 shownin FIGS. 14 and 15.

In this embodiment, a coil spring 40 is interposed instead of theU-shaped leaf spring member 9 shown in FIGS. 14 and 15 between a pair offlat cooling tubes 2A, 2A facing each other.

The central second flat cooling tube 46 in the X-direction coolssemiconductor modules 1 on both sides in the X-direction. Therefore, thesecond high rigid flat cooling tube 46 has a flow path section largerthan that of each of the other flat cooling tubes 2A, 45.

The first and second flat cooling tubes 45, 46 are set to be thick andhave very high rigidity so that no first and second flat cooling tubes45, 46 are easily displaced in the X-direction in comparison with theflat cooling tube 2A. As a result, if a bus bar is wired with thesefirst and second flat cooling tubes 45, 46 as references in connectionof the bus bar to the semiconductor module 1, dispersion of a connectingposition of the bus bar and the semiconductor module 1 is reduced, and aconnecting work of a joining portion can be easily made.

(Modified Mode)

A modified example of the semiconductor device of this embodiment willbe explained with reference to FIGS. 18 and 19. In this embodiment, thecoil spring 40 of the above embodiment shown in FIGS. 16 and 17 ischanged to a leaf spring 41. In accordance with this construction, aninsertion work of the leaf spring 41 is easily made in comparison withthe coil spring 40 so that an assembly process can be simplified.Further, since the leaf spring 41 can face the flat cooling tube 2A overa wide area in comparison with the coil spring 40, the leaf spring 41can further uniformly bias each portion of the flat cooling tube 2Athrough the pinching plate 6.

[Seventh Embodiment]

A coolant cooled type semiconductor device of another embodiment will beexplained with reference to FIGS. 20 to 22. In this embodiment, a cap 47is attached to each of end faces of the flat cooling tube 2A, and eachof end faces is covered with the cap 47. Instead of this, a pair ofheader communication opening portions 48, 48 opened into headers 43, 44in a cooling fluid circulating direction (in the X-direction) is formedin the flat cooling tube 2A.

The headers 43, 44 respectively have elastic sleeve portions 500, 600.The elastic sleeve portions 500, 600 are located between a pair of flatcooling tubes 2A, 2A nipping the semiconductor module 1, and have abellows shape in both end openings each surrounding the headercommunication opening portion 48 and soldered to the flat cooling tube2A. The headers 43, 44 also respectively have rigid sleeve portions 501,601. The rigid sleeve portions 501, 601 are located between a pair offlat cooling tubes 2A, 2A adjacent to each other on a non-existing sideof the semiconductor module 1, and have a straight tube shape in bothend openings each surrounding the header communication opening portion48 and soldered to the flat cooling tube 2A. Each of the elastic sleeveportions 500, 600 has a through hole communicated with the headercommunication opening portion 48 and a circumferential wall portionsurrounding the through hole. This circumferential wall portion isconstructed by a short metallic sleeve formed in a bellows shape, etc.Accordingly, both end portions of the flat cooling tube 2A, the elasticsleeve portions 500, 600 and the rigid sleeve portions 501, 601 areintegrated with each other by soldering and the like so as to constitutethe headers.

In accordance with this embodiment, since the elastic sleeve portions500, 600 are formed in the bellows shape easily elastically deformed,the elastic sleeve portions 500, 600 can be extended and contracted bynipping pressure of the U-shaped leaf spring member 9 in accordance withthe thickness of the semiconductor module 1. Thus, the semiconductormodule 1 and the flat cooling tube 2A can preferably come in contactwith each other without curving and deforming the flat cooling tube 2A.Further, a clearance for inserting the semiconductor module between theflat cooling tubes 2A, 2A prior to the insertion of the semiconductormodule 1 can be set to be large so that an insertion work of thesemiconductor module 1 can be easily made. FIG. 22 is a side view of theflat cooling tube 2A seen from the X-direction.

[Eighth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIGS. 23 to 25. In this embodiment, in thesemiconductor device of the above embodiment shown in FIGS. 20 to 22,the rigid sleeve portions 501, 601 are omitted, and a central flatcooling tube 2B except for flat cooling tubes 2A in both end portions inthe X-direction comes in contact with each of semiconductor modules 1, 1on both sides in the X-direction. An entire set of the semiconductormodule and the flat cooling tube is nipped and pressed by a singleU-shaped leaf spring member 9 a in the X-direction.

In accordance with this embodiment, the rigid sleeve portions 501, 601of the above embodiment can be omitted, and the semiconductor device canbe made compact and the number of assembly works can be reduced incomparison with the above embodiment. However, in this embodiment, it ispreferable to uniformly cool each semiconductor module 1 by increasing acooling fluid flow path section of the central flat cooling tube 2A forcooling the semiconductor modules 1 on both sides.

[Ninth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIG. 26. This embodiment is characterized inthat the headers 43, 44 respectively have flange-shaped sleeve portions502, 602 having a large diameter and adjacent to the semiconductormodule 1.

This flange-shaped sleeve portion 501 can easily elastically deformed inthe X-direction so that the flat cooling tube 2A can be displaced oneach of both sides of the semiconductor module 1. When ring-shapedconcave portions are arranged instead of the flange-shaped sleeveportions 502, 602 around the headers 43, 44, similar effects can beobtained, but a problem of an increase in fluid resistance within theheaders 43, 44 is caused.

In this embodiment, portions of the headers 43, 44 between the flatcooling tubes 2A, 2A adjacent to each other without nipping andsupporting the semiconductor module 1 are set to rigid sleeve portions55 a, 65 a having a straight tube shape. However, the flat cooling tube2A can be easily elastically or plastically deformed in the X-directionby setting these header portions to flange-shaped sleeve portions,ring-shaped concave portions or bellows portions.

[Tenth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIGS. 27 and 28.

This embodiment is characterized in that a flat cooling tube 2C on oneside of the semiconductor module 1 is set to be thick and have highrigidity in a thickness direction of the semiconductor module in thesemiconductor device, and a flat cooling tube 2D on the other side ofthe semiconductor module 1 is set to be thin and have low rigidity(easily deformed) in the thickness direction of the semiconductormodule, and the ring-shaped concave portions 51, 61 of the headers 43,44 are omitted.

The above difference in rigidity may be also obtained by changes inmaterials and shapes instead of the construction in which the flatcooling tube 2D is thinly formed in comparison with the flat coolingtube 2C.

In accordance with such a construction, when the flat cooling tube 2A isnipped and pressed by the U-shaped leaf spring 9, the flat cooling tube2A on the low rigid side is curved in a bow shape on a side of thesemiconductor module 1 and comes in close contact with the semiconductormodule 1 as shown in FIG. 27 so that the following effects can beobtained.

The semiconductor module 1 can preferably come in face contact with theflat cooling tube 2C on one side even when an error in size is caused.Accordingly, cooling can be secured.

The position of the semiconductor module 1 in the X-direction can bepositioned with respect to the high rigid flat cooling tube 2C.

At least a central portion of the other flat cooling tube 2 c curved ina bow shape can also come in close contact with the semiconductor module1 by bow-shaped curvature of this flat cooling tube 2 c. Accordingly,great heat radiating performance can be secured in comparison with acase in which there is no such curvature.

It is not necessary to form an elastic deforming structure in theheaders 43, 44 or connecting portions of the headers 43, 44 and the flatcooling tubes 2C, 2D so that the structure becomes simple.

The flat cooling tube 2D of low rigidity may be curved by the U-shapedleaf spring member 9 in the bow shape in the X-direction in an elasticlimit range, and may be also curved in a plastic deforming rangeexceeding the elastic limit.

In this embodiment, connecting tube portions of headers 43 and 44, whichconnect to the flat cooling tubes 2C and 2D, are rigid in comparisonwith those constituted by the opening portions 50, 60 and concaveportions 51, 61 shown in FIG. 14.

Incidentally, both ends of each flat cooling tube 2D or 2C connecting toboth of the header 43 and 44, respectively serve as connecting tubeportions to the header 43 and 44.

[Eleventh Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIG. 29.

In this embodiment, one of a pair of flat cooling tubes nipping thesemiconductor module 1 is set to have low rigidity by a method differentfrom that in the tenth embodiment. Namely, a flat cooling tube 2E isformed as a low rigid portion by boring in both end portions of the flatcooling tube 2A of the third embodiment, for example. The flat coolingtube 2E is also set to be thin and have no partition wall.

Thus, while deformation of the flat cooling tube 2E is restrained bygiving high rigidity to a central portion of the flat cooling tube 2Ecoming in contact with the semiconductor module 1, both end portions ofthe flat cooling tube 2E can be set to have low rigidity. Accordingly,the central portion of the flat cooling tube 2E can preferably come inclose contact with the semiconductor module 1 by biasing the U-shapedleaf spring member 9.

(Modified Mode)

FIG. 32 shows a modified structure of the cooling unit. This modifiedmode adopts a structure in which the flat cooling tube 2E is pressedagainst the semiconductor module 1 by the coil spring 40 alreadydescribed instead of the U-shaped leaf spring member 9.

[Twelfth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIG. 30.

In this embodiment, the flat cooling tube 2A is set to have low rigidityby a method different from that in the tenth or eleventh embodiments.Namely, a central portion 2 f of the flat cooling tube in thisembodiment is connected to a tip portion 2 g of the flat cooling tubeconnected to the headers 43, 44 by a thin flange-shaped sleeve portion 2h having a large diameter. A central portion of the flange-shaped sleeveportion 2 h is formed such that a diameter of this central portion islarger than that of each of both end portions of the flange-shapedsleeve portion 2 h. The same shape as the central portion is formed.

Thus, while deformation of the flat cooling tube is restrained by givinghigh rigidity to the central portion 2 f of the flat cooling tube comingin contact with the semiconductor module 1, the flange-shaped sleeveportion 2 h can be set to have low rigidity. Accordingly, the centralportion 2 f of the flat cooling tube can preferably come in closecontact with the semiconductor module 1 by biasing the U-shaped leafspring member 9.

(Modified Mode)

FIG. 33 shows a modified structure of the cooling unit. In this modifiedmode, the coil spring 40 described above is used instead of the U-shapedleaf spring member 9.

[Thirteenth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIG. 31.

In this embodiment, both end portions of the flat cooling tube are setto have low rigidity by a method different from that in the tenththrough twelfth embodiments. Namely, each of both end portions of theflat cooling tube in this embodiment has a thin flange-shaped sleeveportion 2 i having a large diameter. This flange-shaped sleeve portion 2i has a ring-shaped concave portion 2 k surrounding a thick centralportion 2 f of the flat cooling tube.

(Modified Mode)

FIG. 34 shows a modified mode. In this modified mode, the coil spring 40already described is used instead of the U-shaped leaf spring member 9.

[Fourteenth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIGS. 35A and 35B.

In this embodiment, flat cooling tubes 2A, 2A of the semiconductormodule 1 are formed in the same shape, and are plastically deformed in adirection away from the semiconductor module 1 previously (FIG. 35A),whereby the width of a space for inserting the semiconductor module 1thereinto is sufficiently secured. After the semiconductor module 1 isinserted, the flat cooling tubes 2A, 2A are deformed by biasing theU-shaped leaf spring member 9, and come in contact with thesemiconductor module 1 by a predetermined pressure (FIG. 35B). Thus, aninsertion work of the semiconductor module 1 can be simplified.

The flat cooling tube 45 having low rigidity as described above and theflat cooling tube 2A having high rigidity may be also utilized insteadof the flat cooling tubes 2A, 2A.

[Fifteenth Embodiment]

A coolant cooled type semiconductor device in another embodiment will beexplained with reference to FIGS. 36 and 37.

In this embodiment, a base plate 10000 is arranged below the flatcooling tube 2A in an arranging direction (X-direction) of thesemiconductor modules. The headers 43, 44 are fixed to this base plate1000.

A pair of fixing wall portions 1001 is fixed vertically to the baseplate 1000. Two sets each constructed by a pair of the flat cooling tube2A and the flat cooling tube 2E having low rigidity in comparison withthe flat cooling tube 2A and a semiconductor module 1 pinched by theseflat cooling tubes 2A, 2E are arranged between both the fixing wallportions 1001. Pressing (sandwiching) plates 33, 33 and a wedge-shapedmember 1002 are arranged between both sets. Each of the pressing plates33, 33 comes in close contact with a main face of the flat cooling tube2E on a side opposed to the semiconductor module, and is increased inthickness toward a downward direction. A surface of the pressing plate33 on a side of the wedge-shaped member is set to a slanting face. Thewedge-shaped member 1002 is formed in a shape thinned toward thedownward direction. A bolt is inserted into the wedge-shaped member1002, and a tip portion of the bolt is screwed into the base plate 1000as shown in FIG. 37. Accordingly, the wedge-shaped member 1002 is movedtoward the base plate 1000, so that the wedge-shaped member 1002 thrustthe pressing plates 33, 33 and the flat cooling tubes 2E, 2E in alateral direction parallel to the base plate 1000. As a result,semiconductor modules 1 come in close contact with the flat coolingtubes 2A, 2A by fastening the bolt. The wedge-shaped member 1002 ispushed steady and prevented from returning backward by the bolt.

(Modified Mode)

The pressing plate 33 can be molded integrally with the flat coolingtube 2A.

[Sixteenth Embodiment]

This embodiment will be explained to show another type of semiconductormodule having an object to provide both a semiconductor switching modulecapable of constituting a compact three-phase power inverter circuit,and also a semiconductor device realized by employing this semiconductorswitching module.

FIG. 38 is a sectional view for showing a semiconductor switching modulealong a thickness direction thereof, and FIG. 39 is a sectional view forrepresenting a semiconductor device with employment of thissemiconductor switching module along a thickness direction thereof.

(Structure of Semiconductor Switching Module)

In FIG. 38, reference numeral 201 shows a high-sided plate, referencenumeral 202 indicates a low-sided plate, reference numeral 202 a shows aspacer, reference numeral 203 indicates a middle-sided plate, referencenumeral 203 a represents another spacer, reference numeral 204 a denotesa semiconductor chip provided on the high side, and reference numeral204 b shows a semiconductor chip provided on the low-side. Also,reference numeral 205 shows a soldering layer, reference numeral 206 arepresents a control electrode terminal, reference numerals 207 a and207 b indicate bonding wires, reference numeral 208 denotes a sealingresin portion, reference numeral 209 shows an outer main surface (majorplane) of the low-sided plate 202, reference numeral 11 represents anouter main surface (major plane) of the high-sided plate 201, andreference numeral 212 shows an outer main surface of the middle-sidedplate 203.

The high-sided plate 1, the low-sided plate 202, the spacer 202 a, themiddle-sided plate 203, and the spacer 203 a are plane plates and madeof metal such as tungsten and molybdenum. Alternatively, these membersmay be made of such as copper, or an aluminum alloy.

The semiconductor chip 204 a is interposed between an inner main surfaceof the high-sided plate 201, and one surface of main surfaces of thespacer 203 a. Therefore, semiconductor chip 204 a is joined to boththese surfaces by way of the soldering layer 205. The other surface ofthe main surfaces of the spacer 203 a is joined to an inner main surfaceof the middle-sided plate 203 by the soldering manner.

The semiconductor chip 204 b is interposed between an inner main surfaceof the middle-sided plate 203, and one surface of main surfaces of thespacer 202 a. Therefore, the semiconductor chip 204 b is joined to boththese surfaces by way of the soldering layer 205. The other surface ofthe main surfaces of this spacer 202 a is joined to an inner mainsurface of the low-sided plate 202 by the soldering manner.

The spacers 202 a and 203 a own a difference in thickness thereof whichare capable of absorbing a difference in a thickness between thesemiconductor chip 4 a and the semiconductor chip 204 b, which isdifferent in thickness from the semiconductor chip 204 a. As a result,an outer main surface of the high-sided plate 201 may be made at thesame height with respect to the outer main surface of the low-sidedplate 202. In other words, the outer main surfaces of the high-sidedplate 201 and the low-sided plate 202 is disposed in a substantiallysame plane.

In accordance with this arrangement, both the high-sided plate 201 andthe low-sided plate 202 may be made in close contact with a coolingmember through a thinner electric insulating member, for example, on thesame plane of the cooling member. Thus, the superior double-sidedcooling effect may be achieved with having the simple construction.

In addition, an extra gap can be secured by the spacers 202 a and 203 abetween either the high-sided plate 201 or the low-sided plate 202, andthe middle-sided plate 203, for example, so that a connection member forconnecting the control electrode of the semiconductor chip and thecontrol electrode terminal thereof, e.g., an arranging space of thebonding wire may be secured without any design problem.

The respective plates 201 to 203 own projected terminal portions 210,220, 230 (see FIGS. 40 and 41) which are elongated along either front ina depth direction of a plane in FIG. 38 or rear in the depth directionthereof. The projected terminal portions 210, 220, 230 are connected toexternal bus bars (not shown). FIG. 40 is an exploded diagram forindicating such a semiconductor switching module made before the spacers202 a and 203 a are joined to the semiconductor chips 204 a and 204 b.FIG. 41 is an oblique perspective figure for showing such asemiconductor switching module made after the spacers 202 a and 203 ahave been joined to the semiconductor chips 204 a and 204 b.

It should be understood in this embodiment that the control electrodeterminals 206 a are firstly formed with the respective plates 201 and203 in an integral form, and are cut away from these plates 201 and 203after the wire bonding or the resin molding. Since such a manufacturingmanner is generally known in the normal lead frame resin moldingtechnique, a detailed explanation thereof is omitted. While five sets ofthese control electrode terminals 206 a are illustrated as to a singlesemiconductor chip in the drawings, these control electrode terminalsare constituted by a gate terminal, a drain terminal, a current mirrorsense terminal, and two temperature detecting terminals for detectingthe temperature of the semiconductor chip. If no sensor such astemperature sensor is required, then only both the gate terminal and thedrain terminal may be required in this minimum condition.

It should also be noted that the widths of the respective plates 201 to203 are made wider than those of the spacers 202 a and 203 a, and thus,the respective plates 201 to 203 are further projected from theperipheral portions of the spacers 202 a and 202 b outwardly along theplane direction. As a result, the base portions of the terminals may bejoined to the inner main surfaces of the respective plates 201 to 203,and then, may be projected outwardly along the plane direction.

It should also be noted that the respective plates 201 to 203 haveconnecting holes 201 a, 202 a, and 203 a for connecting these plates tobus bars or electrodes and the like of other element or device and thelike. Screws and the like are fixed through the connecting holes.

The bonding wires 207 a and 207 b are used to connect bonding pads withthe control electrode terminal 206 a. These bonding pads may constitutecontrol electrodes of the semiconductor chips 204 a and 204 b. Thecontrol electrode terminal 206 a is projected outwardly along the planedirection.

The sealing resin portion 208 may be, for example, an epoxy moldingresin, and may mold both the semiconductor chips 204 a and 204 b. Whilethe sealing resin portion 208 covers the side surfaces of the respectiveplates 201 to 203 and also covers the side surfaces of the semiconductorchips 204 a and 204 b, the outer main surfaces 209, 211 and 212 of therespective plates 201, 202 and 203 are exposed, and an edge portion ofthe sealing resin portion 208 along the thickness direction thereof islimited to inner sides rather than the outer main surfaces 209 to 212.As a consequence, the outer main surfaces 209 to 212 can be readily madein close contact with a flat surface of a cooling member.

The soldering layer 205 may be replaced with a solder material, anelectrically conductive adhesive agent and the like. Also, theseelectrically conductive joint materials may be employed for connectingthe spacers 202 a and 203 a to the respective plates 201 to 203.Alternatively, the spacers 202 a and 203 a may be formed with therespective plates 201 and 203 in an integral form.

Apparently, the control electrodes of the semiconductor chips 204 a and204 b may be connected to the control electrode terminals 206 a by thebonding wires 207 a and 207 b or bump joints.

In FIG. 41, while both the low-sided plate and the high-sided plate arearranged on one main side, other components such as the middle-sidedplate and the control electrode are arranged on the opposite side.Alternatively, for instance, both the low-sided plate and themiddle-sided plate may be arranged on one side. Also, the position ofthe low-sided plate may be changed by the position of the middle-sidedplate.

In accordance with the arrangement above described, while a double-sidedcooling functions of the semiconductor chips (modules) are maintained,the single-phase inverter circuit can be formed in a single invertermodule. The single-phase circuit can be made compact and also a totalnumber of assembling steps can be reduced, whereby when thesemiconductor module is applied to a vehicle, for example, an anxietyabout loosening of fastening portions with respect to vehicle vibrationsand others can be mitigated.

Also, since the middle-sided plate (either output electrode bus bar ofsingle-phase inverter circuit or a portion thereof) may constitute acommon board of both the semiconductor chips, the high packagingarrangement of both the semiconductor chips can be realized. Moreover, atotal number of wiring components can be reduced, a total number ofconnecting steps can be decreased, and loss occurred in the wiring linescan be reduced.

(Modification Mode)

A modification mode of the present invention is shown in FIG. 42.

In the above-explained embodiment, the semiconductor chips 204 a and 204b are constructed of the MOS transistors. In FIG. 42, an IGBT isemployed as these semiconductor chips 204 a and 204 b. In the case thatan IGBT is employed so as to control switching of an inductive load, aflywheel diode must be cross-coupled to this IGBT. As a result, asemiconductor chip 204 c in which the flywheel diode is formed isconnected parallel between the respective plates 201 and 203, andanother semiconductor chip 204 d in which the flywheel is formed isconnected parallel between the respective plates 202 and 203.

Also, in FIG. 42, a projected terminal portion 230 of the middle-sidedplate 203 is extracted along the same direction to the projectedterminal portion 210 of the high-sided plate 201 and the projectedterminal portion 220 of the low-sided plate 202.

Furthermore, in this modification, the control electrode terminal 206 ais projected to a side opposite to the projected terminal portions 210,220, and 230 of the respective plates 201 to 203. As a result, thewiring lines can be easily detoured and the electric insulation can beeasily made between the terminals and the wiring lines. Entering of theswitching noise into the control electrode terminal 206 a can bereduced.

In FIG. 42, the semiconductor chip is constituted by both a transistorchip and a flywheel diode chip, which are interposed in a parallelmanner between one of the high-sided plate 201 and the low-sided plate202 and the middle-sided plate 203, while being separated from eachother.

In accordance with this construction, each of the semiconductor chipsowns such a two-chip structure that one of an IGBT (insulated-gatebipolar transistor), an MOST (insulated-gate transistor) and a BPT(bipolar transistor), for example, and a flywheel diode are connected ina parallel manner, so that a compact single-phase large current invertercircuit having the superior cooling characteristic can be realized.

It should be noted that since a thickness of either an IGBT chip or aBPT chip is normally different from a thickness of a flywheel diodechip, a difference in thickness between these chips may be solved byinterposing one pair of spacers having a difference in thickness betweenthe high-sided plate 201 and the middle-sided plate 203, and alsobetween the low-sided plate 202 and the middle-sided plate 203,respectively.

Incidentally, the spacers 202 a and 203 a may also own projectedterminal portions elongated from the sealing resin portion 208 along adirection substantially equal to a plane direction instead of theterminal 210, 220 or 230.

According to this arrangement, since the spacers are projected from thesealing resin portions along the plane direction so as to constitute theterminals, the simple terminal structures having high reliability can berealized.

Moreover, main electrode terminals may be joined to inner main surfacesof the high-sided plate 201, the low-sided plate 202, and themiddle-sided plate 203, and also are projected outside along the planedirection instead of the terminal 210, 220 or 230 formed in therespective plates 201, 202 and 203.

With employment of such a structure, for instance, low-cost terminalshaving very low resistance values, made of copper and the like, can beemployed as compared with electric resistance values of Mo and W.

Furthermore, it is preferably that a metal material having a coefficientof linear expansion approximately equal to that of the semiconductorchip is employed as the spacers and the middle-sided plate and the. Theshape of this metal material may be easily processed, and also both thematerial cost and the shape-processing cost may be reduced.

(Structure of Semiconductor Device)

A semiconductor device with employment of this semiconductor switchingmodule is indicated in FIG. 39.

Reference numerals 221 and 221 show cooling members corresponding toheat radiation fins. Reference numeral 233 shows an insulating material,and reference numeral 234 represents a silicon grease layer.

The insulating material 233 is made in close contact with the outer mainsurfaces 209 and 211 of the respective plates 201 and 202. A silicongrease layer may be coated or interposed between both the outer mainsurfaces 209 and 211. The cooling member 221 is made in close contactwith flat contact planes of the cooling members 221 and 221 through thesilicone grease layer 234. A large number of concave/convex portions,namely fin are formed on the outer main surfaces of the plates 201 and202.

In FIG. 39, through holes are formed in both a right edge portion and aleft edge portion of the cooling members 221 and 221. A through bolt 231is inserted into these through holes, and a nut 232 is screwed to thethrough bolt 231, so that the semiconductor switching module is pinchedby one pair of these cooling members 221 and 221. In other words, inaccordance with this embodiment, these cooling members 221 and 221 maywork not only the cooling member but a force-transferring member so thatthe pinching force produced by the bolt and the nut is transferred tothe contact planes in order that the cooling members 221 and 221 can bemade in close contact with the semiconductor switching module underbetter condition. Alternatively, these heat-radiating members 221 and221 may be replaced by, for instance, the coolant tube as describedabove embodiments.

FIG. 39 represents such a condition that the cooling members 221 and 221pinch only one phase of the semiconductor switching module in thethree-phase inverter system (namely, single-phase inverter circuit).Alternatively, these cooling members 221 and 221 may sandwich the othertwo phases of the semiconductor switching modules at the same timetoward the rear depth direction of the plane in FIG. 38.

[Seventeenth Embodiment]

Referring now to FIG. 43, a description will be made of a semiconductorswitching module according to another embodiment, and also asemiconductor device for constituting a 3-phase inverter circuit withemployment of this switching module. FIG. 43 is a plan view forindicating a major portion of this semiconductor device.

In this embodiment, FIG. 43 shows a plan view of a semiconductorswitching module 300 containing the 3-phase inverter circuit in whichthree sets of the single-phase inverter circuit shown in FIG. 42 areintegrated inside the sealing resin portion 208.

Also, in this embodiment, while the semiconductor switching module 300is pinched by the cooling members 221 and 221 shown in FIG. 39 from bothsides thereof, a semiconductor device which constitutes an one module ofa 3-phase inverter circuit may be realized.

It should be noted that symbol 203U shows a middle-sided plate for aU-phase, symbol 203V indicates a middle-sided plate for a V-phase, andsymbol 203W represents a middle-sided plate for a W-phase, which arearranged in parallel to each other. One edge of each of thesemiddle-sided plates constitutes a projected terminal portion 30U, 30V,or 30W, respectively.

While the semiconductor chips 204 a and 4 b in which the IGBT is formed,respectively, the semiconductor chips 204 c and 204 d in which theflywheel diode is formed, respectively. The respective flywheel diodesare cross-coupled to the respective IGBTs similar to the above-mentionedsemiconductor switching module.

Although a control electrode terminal is not shown in this drawing, thecontrol electrode terminal may be formed by way of a so-called “leadframe manufacturing process.”

Namely, the three-phase semiconductor switching module has a high-sidedsemiconductor chip in which a high-sided semiconductor switching elementis formed, and a low-sided semiconductor chip in which a low-sidedsemiconductor switching element is formed. The three-phase semiconductorswitching module is also arranged by connecting three sets of asingle-phase inverter circuit in a parallel manner. The single-phaseinverter circuit is arranged by series-connecting both the semiconductorswitching elements.

The three-phase semiconductor switching module comprises of a high-sidedplate and a low-sided plate, which are made of metal platesrespectively, and also middle-sided plates of a U-phase, a V-phase, anda W-phase;

Main electrode surfaces of both the semiconductor chips for the U-phaseon the output sides thereof are directly joined, or joined viaelectrically conductive members to an inner main surface of themiddle-sided plate for the U-phase, while the main electrode surfacesthereof are separated from each other.

Main electrode surfaces of both the semiconductor chips for the V-phaseon the output sides thereof are directly joined, or joined viaelectrically conductive members to an inner main surface of themiddle-sided plate for the V-phase, while the main electrode surfacesthereof are separated from each other.

Main electrode surfaces of both the semiconductor chips for the W-phaseon the output sides thereof are directly joined, or joined viaelectrically conductive members to an inner main surface of themiddle-sided plate for the W-phase, while the main electrode surfacesthereof are separated from each other.

A main electrode surface of the high-sided semiconductor chip for eachphase on the side of a high potential power supply is directly joined,or joined via an electrically conductive member to an inner main surfaceof the high-sided plate.

A main electrode surface of the low-sided semiconductor chip for eachphase on the side of a low potential power supply is directly joined, orjoined via an electrically conductive member to an inner main surface ofthe low-sided plate.

Both the semiconductor chips are covered in an integral form by asealing resin portion, which is molded, while exposing outer mainsurfaces of the middle-sided plate for each phase, the high-sided platefor each phase, and the low-sided plate for each phase.

In accordance with this arrangement, the three-phase inverter circuit isbuilt in the semiconductor switching module, while employing fivebus-bar-shaped members in total, namely the high-sided plate, the threemiddle-sided plate, and the low-sided plate. Furthermore, it is possibleto realize such a module that the respective semiconductor chips arearranged in a matrix shape in a constant interval. Therefore, thearrangement of the semiconductor switching module can be considerablysimplified, and also can output high power by cooling both surfacesthereof, while this semiconductor switching module can be made compact.

[Other Embodiments]

Embodiments explained below show semiconductor devices for largeelectric power, which are easily manufactured so as to be excellent inpractical property, and have an excellent heat radiatingcharacteristics.

Preferred modes of the present invention will be explained withreference to the following embodiments.

[Eighteenth Embodiment]

(Entire Construction)

FIG. 44 is a circuit diagram of a three-phase inverter circuit devicefor controlling an operation of a driving motor of an electricautomobile.

Reference numeral 221 designates a battery (direct current powersource). Each of reference numerals 222 to 227 designates asemiconductor element constructed by an NMOS transistor utilizing aparasitic diode as a flywheel diode.

The semiconductor element 222 constitutes a U-phase upper arm, and thesemiconductor element 223 constitutes a U-phase lower arm. Thesemiconductor element 224 constitutes a V-phase upper arm, and thesemiconductor element 225 constitutes a V-phase lower arm. Thesemiconductor element 26 constitutes a W-phase upper arm, and thesemiconductor element 227 designates a W-phase lower arm. Thesesemiconductor elements are individually mounted as semiconductor modules150 to 650, respectively.

Reference numerals 151 and 152 respectively designate a positive directcurrent power source terminal (drain side) of the U-phase upper (highside) arm, and an alternating current output terminal (source side) ofthe U-phase upper arm. Reference numerals 251 and 252 respectivelydesignate an alternating current output terminal (drain side) of theU-phase lower (low side) arm, and a negative direct current terminal(source side) of the U-phase lower arm.

Reference numerals 351 and 352 respectively designate a positive directcurrent power source terminal (drain side) of the V-phase upper (highside) arm, and an alternating current output terminal (source side) ofthe V-phase upper arm. Reference numerals 451 and 452 respectivelydesignate an alternating current output terminal (drain side) of theV-phase lower (low side) arm, and a negative direct current terminal(source side) of the V-phase lower arm.

Reference numerals 551 and 552 respectively designate a positive directcurrent power source terminal (drain side) of the W-phase upper (highside) arm, and an alternating current output terminal (source side) ofthe W-phase upper arm. Reference numerals 651 and 652 respectivelydesignate an alternating current output terminal (drain side) of theW-phase lower (low side) arm, and a negative direct current terminal(source side) of the W-phase lower arm.

Each of the positive direct current power source terminals 151, 351, 551is connected to a positive electrode terminal of a smoothing capacitor228 and a positive electrode terminal of the battery 221. Each of thenegative direct current power source terminals 252, 452, 652 isconnected to a negative electrode terminal of the smoothing capacitor228 and a negative electrode terminal of the battery 221. The U-phasealternating current output terminals 152, 251 are connected to eachother at a connection point 153. The V-phase alternating current outputterminals 352, 451 are connected to each other at a connection point353. The W-phase alternating current output terminals 552, 651 areconnected to each other at a connection point 553. Thus, electric poweris supplied to a armature winding (not shown) of a three-phasealternating current motor 229.

A controller 130 outputs a control voltage to a gate electrode of eachsemiconductor element, and detects a temperature of each semiconductorelement, etc. Operations of the above three-phase inverter circuit andthe smoothing capacitor 228 are well known. Accordingly, a detailedexplanation of these operations is omitted here.

(Semiconductor Module)

A semiconductor module 150 of the U-phase upper arm will next beexplained with reference to FIGS. 45A and 45B. FIGS. 45A and 45Brespectively show an exploded perspective view of this semiconductormodule and a perspective view of the entire semiconductor module.

Reference numerals 155, 156 and 158 respectively designate a metallicheat transfer plate having the positive direct current power sourceterminal 151, a metallic heat transfer plate having the alternatingcurrent output terminal 152, and a signal terminal (also called acontrol electrode terminal) of the semiconductor element (asemiconductor element chip for large electric power) 222. The signalterminal 158 includes a terminal for controlling the operation of a gateelectrode of an NMOS transistor, and a signal terminal for an internalmonitor of the semiconductor element 222. Five signal terminals 158 arearranged in each of FIGS. 45A and 45B.

The semiconductor element 222 is soldered onto the metallic heattransfer plate 155, and the metallic heat transfer 156 is soldered ontoan upper face of the semiconductor element 222. These metallic heattransfer plates are sealed by resin 159 in a state in which externalmain faces of the metallic heat transfer plates 155, 156 are exposed andterminals 151, 152, 158 are projected. These members constitute thesemiconductor module 150.

In this embodiment, the signal terminal 158 and the positive directcurrent power source terminal (also called a drain electrode terminal)151 are particularly arranged on the same side (particularly, a longside) of the rectangular semiconductor module 150. The signal terminal158 is arranged on a half side of this long side, and the positivedirect current power source terminal (drain electrode terminal) 101 isarranged on the other half side of this long side as shown in FIG. 45B.The alternating current output terminal (also called a source electrodeterminal) 152 is arranged in a half portion on a side opposed to theside from which terminals 158, 151 are projected. Namely, thealternating current output terminal 152 is projected in a directionopposite to the signal terminal 158.

Here, heat resistance from a junction portion of the semiconductorelement (NMOS transistor) 222 to the metallic heat transfer plate 155 ona drain side in the semiconductor module 150 is set to R1. Heatresistance from the junction portion of the semiconductor element 222 tothe metallic heat transfer plate 156 on a source side is set to R2. Ifthickness of both the metallic heat transfer plates 155, 156 are set tobe equal to each other, a relation between R1 and R2 becomes “R1<R2”.

The reasons are as follows. A main face of the semiconductor element 222disposed on its drain area side is joined to the metallic heat transferplate 105 over an entire face of this main face. In contrast to this,with respect to a main face of the semiconductor element 222 disposed onits source area side, it is necessary to project one portion of themetallic heat transfer plate 156 disposed on a source side toward thesemiconductor element 222 so as to secure a three-dimensional space forconnection with each signal terminal 158 using wiring bonding and avoidthis three-dimensional space. Therefore, only the remaining portionobtained by subtracting the above three-dimensional space from the mainface of the semiconductor element 222 disposed on its source area sidecan be joined to the metallic heat transfer plate 156. Therefore, theabove-mentioned heat resistance relation is formed.

The semiconductor modules 350, 550 of the other upper arms have the sameconstruction as the semiconductor module 150. The semiconductor modules250, 450, 650 of the lower arms also have the same construction as thesemiconductor modules 150, 350, 550 of the upper arms. In this case, thepositive direct current power source terminal of the semiconductormodule of the upper arm is replaced with an alternating current Outputterminal in the semiconductor module of the lower arm, and thealternating current output terminal of the semiconductor module of theupper arm is replaced with a negative direct current power sourceterminal in the semiconductor module of the lower arm.

When an IGBT is adopted as the semiconductor module 222, a separateflywheel diode is required. However, the flywheel diode may be arrangedon a left-hand side of the semiconductor element 222 in FIG. 45A. Inthis case, the flywheel diode is mounted in a shape in which a cathodeside of the flywheel diode is directed to the metallic heat transferplate 155 having the positive direct current power source terminal 151.

(Semiconductor Module)

FIG. 46 shows the semiconductor module 250.

Reference numerals 255, 256, 258 and 259 respectively designate ametallic heat transfer plate having the alternating current outputterminal 251, a metallic heat transfer plate having the negative directcurrent power source terminal 252, a control electrode terminal of thesemiconductor element 223, and mold resin.

FIGS. 47 and 48 show an inverter device using the semiconductor module250. FIG. 48 shows a side view of this inverter device. FIG. 47 is apartial plan view of a U-phase portion, and FIG. 48 is a side view seenfrom an arrow XXXXVIII of FIG. 47.

A heat sink 110 is constructed by a metallic plate of a water coolingstructure forming a cooling flow path therein. For example, the heatsink 110 is formed by an aluminum die-cast method. The heat sink 110 isnot limited to water cooling. For example, the heat sink 110 may beconstructed by a flat tube formed by extrusion or drawing of aluminum(Al) having strength and an airtight (sealing) property able to seal arefrigerant of an air conditioner for an automobile and the like, andmay be also constructed by a well-known refrigerant reservoir of aboiling-cooling type.

Each of reference numerals 150, 250 designates a semiconductor module(hereinafter, also called a card type semiconductor module). Referencenumeral 112 designates a fixing member (a biasing-holding member in thepresent invention). A pair of fixing members 112 is detachably fixed tothe heat sink 110 by screws 113 from above the semiconductor modules150, 250. The fixing members 112 individually press the semiconductormodules 150, 250 against an upper face of the heat sink 110.

A smoothing capacitor 228 is adjacent to the semiconductor modules 50,250, and is fixed onto the heat sink 110 in a posture in which a bottomface of the smoothing capacitor 228 comes in contact with the heat sink.Reference numerals 111+ and 111− respectively designate a positivedirect current input bus bar and a negative direct current input bus barwhich are also respectively the direct current input terminals 151, 251of the semiconductor modules 150 and 250, and positive and negativeelectrodes of the smoothing capacitor 228.

An insulator 1111 is interposed to electrically insulate the positiveand negative direct current input bus bars 111+, 111−. Reference numeral121 designates an alternating current output bus bar of the U-phaseconnecting the alternating current output terminals 152, 251 of thesemiconductor modules 150, 250 and the three-phase alternating currentmotor 229. Constructions with respect to the V-phase and the W-phase aresimilar to the construction with respect to the U-phase. Accordingly, anexplanation of these constructions are omitted here.

The controller 130 is arranged in parallel with the heat sink 110 abovethe semiconductor modules 150, 250 although this arrangement is notillustrated here. The controller 130 is connected to control electrodeterminals 158, 258 of the respective semiconductor modules 150, 250,etc.

A member having a heat conducting property and an electric insulationperformance, e.g., an insulation heat radiating sheet of a siliconesystem is nipped on a contact face 115 of each of the semiconductormodules 150, 250 and the heat sink 110, and a contact face 116 of eachof the semiconductor modules 150, 250 and the fixing member 112.However, this insulation heat radiating sheet can be replaced with aninsulating substrate such as ceramics, etc., and heat radiating greaseon both faces of this insulating substrate. A heat radiating sheet of asilicone system having a good heat conducting property and a heatconducting grease, etc. are also interposed on a contact face 117 of thefixing member 11112 and the heat sink 110. If the fixing member is aninsulating member such as resin, etc., no electric insulating propertyis required in the heat conducting members nipped on the contact faces116 and 117.

In accordance with the above embodiment, the semiconductor module 150 isstably held in the heat sink 110 without using solder joining.Accordingly, it is not necessary to consider life of solder, so thatlife of the entire semiconductor device can be extended. Since no solderjoining is used, it is not necessary to use an expensive material suchas Al—SiC, etc. in the heat sink 110 so that cost of the entiresemiconductor device can be reduced.

Further, the semiconductor device can be assembled by a simplemanufacture arrangement irrespective of large heat capacity of the heatsink 110. Since the semiconductor device is constructed so as to bemechanically detached, the semiconductor device is excellent in recycleproperty and is easily exchanged.

Further, heat can be radiated from both faces of the semiconductorelement within the semiconductor module to the heat sink 110 by applyingthe fixing member 112 made by a metallic material having a good heatconducting property, e.g., Cu and aluminum. Accordingly, heat radiatingperformance can be greatly improved in comparison with a case in whichheat is radiated from one face of the semiconductor element. As aresult, the semiconductor element can be made compact so that thesemiconductor device can be made compact and reduced in cost. One fixingmember 112 may be prepared every semiconductor module, and a lot ofsemiconductor modules may be also fixed by one fixing member

(Fixing Member)

The fixing member 112 will be further explained with reference to FIG.49. FIG. 49 is a side view of a main portion of this device.

The fixing member 112 has a beam portion 1121 for pressing and biasingthe semiconductor module, and a pair of leg portions 1122 projected fromboth ends of the beam portion 1121 to a side of the beat sink 110. Ahole (not shown) extends through each of both the leg portions 1122 in athickness direction of the semiconductor module 150. The fixing member112 is fixed to the heat sink 110 by fastening a screw 113 to the heatsink 110 through this hole. The semiconductor module 150 is nipped andpressed by the heat sink 110 and the beam portion 1121 of the fixingmember 112.

An insulation heat conducting member 120 is arranged between a metallicheat radiating plate (not shown) of the semiconductor module 150disposed on its heat sink side and an upper face of the heat sink 110.The insulation heat conducting member 120 is also arranged between ametallic heat radiating plate (not shown) of the semiconductor module150 disposed on a side opposed to the heat sink and a lower face of thebeam portion 1121 of the fixing member 112. A heat conducting member 122is arranged between a lower face of the leg portion 1122 of the fixingmember 112 and the upper face of the heat sink 110.

In this embodiment, the heat conducting member 122 is constructed by asoft material having a good heat conducting property, and is softer thanthe insulation heat conducting member 120.

In such a construction, when the fixing member 120 is fastened to theheat sink 110 by the screw 113, the semiconductor module 150 can bestrongly pressed against the heat sink 110 by the hard heat conductingmember 120. Accordingly, heat can be preferably radiated from a lowerside face of the semiconductor module 150 to the heat sink 110. Amaterial softer than the insulation heat conducting member 120 is usedin the heat conducting member 122 so that the insulation heat conductingmember 120 fully fits the lower face of the leg portion 1122 and theupper face of the heat sink 110, and heat resistance can be reduced.

For example, aluminum nitride and a hard silicone rubber sheet can beadopted as the insulation beat conducting member 120. For example,solder, heat conducting grease and a graphite sheet can be adopted asthe heat conducting member 122. A material having an electric insulatingproperty, e.g., a silicone rubber sheet having low hardness may be alsoadopted as the heat conducting member 122. The screw 113 may bemanufactured by a metal, and may be also manufactured by resin having anelectric insulating property.

(Modified Mode)

In the above embodiment, the insulation heat conducting member 120 isnipped between the semiconductor module 150 and the beam portion 1121 ofthe fixing member 112. However, the heat conducting member 122 may bechanged to an insulation heat conducting member having an electricinsulating property, and the insulation heat conducting member 120 maybe also set to a conducting member having an electric conductingproperty. The semiconductor module 150 and the beam portion 1121 of thefixing member 112 may come in direct contact with each other. Resin isused in the screw 113. In such a construction, the fixing member 112 canbe used as a wiring member or a terminal connected to the metallic heatradiating plate of the semiconductor module 150 on a side opposed to theheat sink.

[Nineteenth Embodiment]

Another embodiment will next be explained with reference to FIG. 49.

In this embodiment, an average coefficient km1 of thermal expansion ofthe leg portion 1122 of the fixing member 112 and the heat conductingmember 122 is set to be in conformity (within an error of 1%) with anaverage coefficient km2 of thermal expansion of the semiconductor module150 and two insulation heat conducting members 120 between a pair ofmetallic heat radiating faces. In this specification, an averagecoefficient km of thermal expansion of plural members A, B is set to beprescribed by the following formula.

 km=(k1□t1+k2□t2)/(t1+t2)

Here, k1 is a coefficient of thermal expansion (a coefficient of linearexpansion) of the member A, t1 is a thickness of the member A, k2 is acoefficient of thermal expansion (a coefficient of linear expansion) ofthe member B, and t2 is a thickness of the member B.

In such a construction, it is possible to dissolve thermal stress causedby the difference in coefficient of thermal expansion between thesemiconductor module 150 and the leg portion 1122 so that reliabilitywith the passage of time can be improved. The above difference incoefficient of thermal expansion is allowed if this difference lies in arange in which this difference has no bad influence on each portion ofthe semiconductor module at a maximum using temperature or a minimumusing temperature.

(Modified Mode)

In conformity setting of this average coefficient of thermal expansion,temperatures of the leg portion 1122 of the fixing member 112, the heatconducting member 122, the semiconductor module 150 and the twoinsulation heat conducting members 120 are respectively different fromeach other. Therefore, expansion amounts of these members, etc. in theirthickness directions are different from each other.

A material of the leg portion 1122, etc. can be selected to compensatethe difference in expansion amount due to the difference in temperaturebetween these respective parts such that a total expansion amount of theleg portion 1122 of the above fixing member 112 and the heat conductingmember 122 in the thickness direction is conformed to that of thesemiconductor module 150 and the two insulation heat conducting members120 in the thickness direction at the maximum using temperature at whichthe expansion amount is maximized. Further, the material of the legportion 1122, etc. can be selected such that the above difference inexpansion amount lies in an allowable range at each using temperature ofthe semiconductor module 100.

[Twentieth Embodiment]

Another embodiment will next be explained with reference to FIG. 50.

In this embodiment, a main cooling fluid passage M is formed within theheat sink 110, and a cooling fluid flows through this passage M. Asub-cooling fluid passage S is also formed in the fixing member 112.Both end openings of the sub-cooling fluid passage S of the fixingmember 112 are communicated with the main cooling fluid passage M of theheat sink 110. Both the passages M, S are substantially connected inseries or parallel to each other. Thus, the semiconductor module 150 canbe further preferably cooled.

Reference numeral 360 designates a packing. This packing 360 can alsohave a function for elastically absorbing thermal stress due to thedifference in coefficient of thermal expansion between the fixing member112 and the semiconductor module 100 in the thickness direction of thesemiconductor module 100. Reference numeral 120 designates an insulationheat conducting member for electrically insulating the metallic heatradiating plate of the semiconductor module 150, the heat sink 110 andthe fixing member 112.

In this embodiment, the cooling fluid flows through the fixing member,but the fixing member may be constructed by a heat pipe and may be fixedto the heat sink.

[Twenty-First Embodiment]

Another embodiment will next be explained with reference to FIG. 51.

In this embodiment, other circuit parts (a smoothing capacitor in thisembodiment) are overlapped and arranged on the semiconductor modules150, 250 through bus bars 161, 262. The fixing member 112 presses thesemiconductor modules 150, 250 against the heat sink 110 through thesmoothing capacitor 228.

In such a construction, circuit mounting density can be improved.Further, it is possible to shorten the wiring distance between thesemiconductor module 150 constituting an inverter circuit and thesmoothing capacitor 228 absorbing a switching serge voltage between apair of direct current terminals of this semiconductor module 150.Accordingly, electric power loss and generated loss due to wiringresistance can be reduced. The smoothing capacitor 228 and the bus bars161, 262 can have a heat sink function of the semiconductor module 150.In other words, the bus bars 151 and 252 serve like the metallic heattransfer plate 155 and the metallic heat transfer plate 256.

The metallic heat radiating plate of each of the semiconductor modules150, 250 on a side opposed to the heat sink constitutes a + or − directcurrent terminal of the inverter circuit. The metallic heat radiatingplate (not shown) of each of the semiconductor modules 150, 250 on aheat sink side constitutes an alternating current output terminal. Thetwo semiconductor modules 150, 250 are nipped and pressed by one fixingmember 112.

Each of the bus bars 161, 262 has a concave portion c into which each ofa + direct current terminal 281 and a − input terminal 282 of thesmoothing capacitor 228 is fitted. Thus, a transversal shift of thesmoothing capacitor 228 can be prevented, and a position of thesmoothing capacitor is easily aligned at its mounting time. A side faceof this concave portion c is set to a taper face having a graduallynarrowed bottom so that both direct current terminals 281, 282 of thesmoothing capacitor 228 are easily fitted and aligned in position. Thesmoothing capacitor 228 can have plural + direct current terminals 281and plural − direct current terminals 282. In this case, a plurality ofsaid concave portions fitted to these terminals are arranged.

(Modified Mode)

In this embodiment, a material of the leg portion 1122, etc. areselected such that an average expansion coefficient km3 of thesemiconductor modules 150, 250, the smoothing capacitor 228 and the busbars 161, 262 in the thickness direction of the semiconductor module 150is conformed to an average expansion coefficient km4 of the leg portion1122 of the fixing member 112 in its thickness direction.

Similarly to the above formula, each of the average expansioncoefficients km3, km4 is defined as a value obtained by dividing a totalexpansion amount per rise in unit temperature of plural constructionalmembers by a total distance of these plural members in their thicknessdirections. Otherwise, similarly to the above modified mode, while theactual expansion amount of each portion in its thickness direction isset by considering a temperature distribution at a predeterminedtemperature (normally a maximum using temperature) of the semiconductormodules 150, 250, the expansion amounts in the thickness direction onboth of the leg portion 1122 and the semiconductor modules 150, 250 maybe set to be in conformity with each other. In any case, the problem ofthermal stress as a serious problem in a fixing system of the pinchingsemiconductor module of this construction can be solved at a practicallevel.

[Twenty-Second Embodiment]

Another embodiment will next be explained with reference to FIG. 51.

In this embodiment, the bus bars 161, 262 are set to metallic heatradiating plates of the semiconductor module 150 on a side opposed tothe heat sink in a two-story circuit structure of the twenty-firstembodiment shown in FIG. 51. Accordingly, in this embodiment, themetallic heat radiating plates 161, 262 of the semiconductor modules150, 250 on the side opposed to the heat sink respectively have concaveportions c into which a + direct current terminal 281 and a − minusinput terminal 282 of the smoothing capacitor 228 are fitted. Thus, atransversal shift of the smoothing capacitor 228 can be prevented, and aposition of the smoothing capacitor is easily aligned at its mountingtime. The other effects are the same as the twenty-first embodiment.

(Modified Mode)

In this embodiment, the material of the leg portion 1122, etc. areselected such that an average expansion coefficient km5 of thesemiconductor modules 150, 250 and the smoothing capacitor 228 in thethickness direction of the semiconductor module 150 is conformed to anaverage expansion coefficient km6 of the leg portion 1122 of the fixingmember 112 in its thickness direction. The average expansioncoefficients km5, km6 are calculated by the above formula althoughexplanations of these calculations are omitted. Similarly to theabove-modified mode, while the actual expansion amount of each portionin its thickness direction is set by considering a temperaturedistribution at a predetermined temperature (normally a maximum usingtemperature) of the semiconductor modules 150, 250, the expansionamounts in the thickness direction on both of the leg portion 1122 andthe semiconductor modules 150, 250 may be also conformed to each other.In any case, the problem of thermal stress as a serious problem in afixing system of the pinching semiconductor module of this constructioncan be solved at a practical level.

[Twenty-Third Embodiment]

Another embodiment will next be explained with reference to FIG. 52.

In this embodiment, the fixing member 112 has an elastic deformingportion 1123 having a curving shape in which a beam portion 1121particularly has a large elastic modulus toward the thickness directionof the semiconductor module 150. In such a construction, it is possibleto greatly reduce the thermal stress caused by the difference incoefficient of thermal expansion already described between thesemiconductor module 150 and the leg portion 122 in the thicknessdirection of the semiconductor module 150.

[Twenty-Fourth Embodiment]

Another embodiment will next be explained with reference to FIG. 53.

In this embodiment, the heat sink 110 has a pair of side wall portions111 projected on both sides of the semiconductor module 150, and thefixing member 112 is formed by a metallic thin plate. Both end portionsof the fixing member 112 are fixed to the side wall portions by screws113 manufactured by resin.

In accordance with this construction, the fixing member 112 can beeasily elastically deformed in the thickness direction of thesemiconductor module 150 so that the above thermal stress can bepreferably absorbed. Further, the heat radiating distance between theheat sink 110 and a metallic heat radiating plate of the semiconductormodule 150 on a side opposed to the heat sink is shortened. Accordingly,a reduction in heat radiating property can be restrained although thefixing member 112 is made thin.

[Twenty-Fifth Embodiment]

Another embodiment will next be explained with reference to FIG. 54.

In this embodiment, the metallic heat radiating plate 156 of thesemiconductor module 150 on a side opposed to the beat sink has anirregular portion 1061 fitted to an irregular portion 11211 of a beamportion 1121 of the fixing member 112. A metallic heat radiating plate(not shown) of the semiconductor module 100 on a heat sink side and aleg portion 1122 of the fixing member 112 respectively come in closecontact with the heat sink 110 through insulation heat conductingmembers having an electric insulating property. A screw 113 ismanufactured by resin. A side face of the irregular portion is set to ataper face so as to easily fit and position the irregular portion. Thus,the fixing member 112 is easily positioned with respect to thesemiconductor module 150 so that a transversal shift of thesemiconductor module 150 can be prevented, and the heat resistancebetween the semiconductor module 150 and the fixing member 112 can bereduced. The fixing member 112 can be also used as a terminal of themetallic heat radiating plate 156 of the semiconductor module 150 on theside opposed to the heat sink.

This irregular fitting structure can be also used in contact of themetallic heat radiating plate of the semiconductor module 150 on theheat sink side and the heat sink 10. However, in this case, the metallicheat radiating plate of the semiconductor module 150 on the heat sinkside is preferably set to have the same electric potential (normallyground electric potential) as the heat sink.

[Twenty-Sixth Embodiment]

Another embodiment will next be explained with reference to FIG. 55.

In this embodiment, the heat sink 110 has a stopper 1101 coming incontact with a resin mold portion 159 of the semiconductor module 150and regulating a transversal shift of the semiconductor module 150.Thus, no semiconductor module is transversally shifted from the heatsink or a biasing-holding member even in a high vibration environmentsuch as an electric automobile so that reliability can be improved.Since a side face of this stopper 1101 is set to a taper face (slantingface), the semiconductor module 150 is easily positioned.

(Modified Mode)

In the above modified mode, the stopper is arranged in the heat sink110, but may be also arranged in the fixing member 112 so as to preventthe transversal shift of the semiconductor module 150. In this case, thesemiconductor module 150 is easily positioned by setting the side faceof the stopper to a taper face (slanting face).

[Twenty-Seventh Embodiment]

Another embodiment of the inverter device of the present invention willbe explained with reference to FIGS. 56 and 57. FIG. 56 is a partialplan view of a U-phase portion. FIG. 57 is a side view seen from anarrow LVII of FIG. 56.

The heat sink 110 is constructed by a metallic plate of a water coolingstructure forming a cooling flow path therein. For example, the heatsink 110 is formed by a die-cast method. Reference numeral 150designates a card type semiconductor module. The structure of the cardtype semiconductor module 150 is already explained in the eighteenthembodiment.

The card type semiconductor module (also called a semiconductor module)150 is detachably fixed by fastening a screw 113 from above the fixingmember (biasing-holding member) 112. The fixing member (biasing-holdingmember) 112 presses the semiconductor module 150 against an upper faceof the heat sink 110. A semiconductor module 250 of a lower arm has thesame construction as the semiconductor module 150. Similarly to thesemiconductor module 150, the semiconductor module 250 is fixed so as tobe pressed against the heat sink 110 in a state in which thesemiconductor module 250 is horizontally rotated 180 degrees withrespect to the semiconductor module 150 in FIG. 56.

A smoothing capacitor 228 is adjacent to the semiconductor modules 150,250 and is fixed such that a bottom face of the smoothing capacitor 228comes in contact with the heat sink 110. A positive direct current inputbus bar 111+ and a negative direct current input bus bar 111−respectively connect direct current input terminals 151, 252 of thesemiconductor modules 150 and 250, and positive and negative electrodesof the smoothing capacitor 228. An insulator 1111 nips the positive andnegative direct current input bus bars 111+ and 111− so as toelectrically insulate these bus bars from each other. An alternatingcurrent output bus bar 121 of the U-phase connects alternating currentoutput terminals 152, 251 of the semiconductor modules 150, 250 and athree-phase alternating current motor 229. Constructions with respect tothe V-phase and the W-phase are similar to the construction of theU-phase. Accordingly, an explanation of these constructions is omittedhere.

A controller 130 is arranged approximately in parallel with the heatsink above the semiconductor module although this arrangement is notillustrated here. The controller 130 is connected to signal electrodes158, 258 of the respective semiconductor modules, etc.

A member having a heat conducting property and an electrical insulativeproperty, e.g., a heat radiating sheet of a silicone system is pinchedbetween the heat sink 110 and each of the semiconductor modules 150, 250at a contact face 115 and between the biasing-holding member 112 andeach of the semiconductor modules 150, 250 at a contact face 116. Amember having a good heat conducting property, e.g., a heat radiatingsheet of a silicone system, grease, etc. are nipped on a contact face117 of the biasing-holding member 112 and the heat sink 110. If thebiasing-holding member is an insulating member such as resin having agood heat conducting property, etc., no electric insulating property isrequired in the heat conducting member nipped on the contact face 116. Amember having a good heat conducting property may be also similarlynipped on the bottom face of a capacitor and a contact face of the heatsink.

FIG. 56 shows only the U-phase, but a three-phase inverter can be simplyconstructed by arranging similar constructions with respect to theV-phase and W-phase in parallel with each other on a side of FIG. 56.

The other constructions are the same as the eighteenth embodiment. Inaccordance with this embodiment, the following operational effects canbe obtained.

First, semiconductor modules 150 to 650 are mounted to the heat sink 110in a posture in which a main face of the semiconductor modules 150 to650 on a drain area side having small heat resistance among two mainfaces of these semiconductor modules is pressed against the heat sink110 having high cooling performance. Therefore, heat radiating propertyis improved, and the cooling property of a semiconductor element can befurther improved.

Next, as shown in FIGS. 45B and 56, the drain electrode terminal(positive direct current power source terminal) 151 of the semiconductormodule 150 is arranged approximately with rotation symmetry with respectto the source electrode terminal (alternating current output terminal)152 of the semiconductor module 150. In other words, the drain electrodeterminal 151 is arranged at a half portion of one of two longitudinalsides parallel to each other in a rectangular shape of the semiconductormodule 150, which is, positioned in a diagonal direction to a portion ofthe other of two longitudinal sides in which the source electrodeterminal 152 is formed. Namely, the drain electrode terminal 151 isdisposed on the one of the two longitudinal sides parallel to eachother, while the source electrode terminal 152 is disposed on the otherof two longitudinal sides. Additionally, the drain electrode terminal151 and the source electrode terminal 152 are shifted from each other ina direction parallel to the two longitudinal sides.

The signal terminal 158 is arranged at another half of the one of thelongitudinal sides parallel each other described above (another halfportion on a side at which the drain electrode terminal 101 is formed inFIG. 45B). Accordingly, switching elements of six arms of thethree-phase inverter can be reasonably arranged at high density by onekind of card module so that the inverter can be made compact.

Such a construction will be explained further in detail with referenceto FIG. 56. The semiconductor module 150 of an upper arm of the U-phaseand the semiconductor module 250 of a lower arm can be obtained byrotating the semiconductor module 250 180 degrees on the same plane withrespect to the semiconductor module 150 and setting the semiconductormodule 250 to be adjacent to the semiconductor module 150.

The source terminal 152 is projected from the semiconductor module 150in a lower half in FIG. 56 along a pair of long sides opposing andparallel to each other of the semiconductor modules 150 and 250.Similarly, the source terminal 252 is projected from the semiconductormodule 250 in an upper half in FIG. 56. Since these terminals 152, 252are not overlapped, the distance between both the semiconductor modules150, 250 can be shortened so that high density mounting can beperformed. These terminals-have the same construction with respect to apair of semiconductor modules 350 and 450 and a pair of semiconductormodules 550 and 650 in the other phases.

The positive direct current input bus-bar 111+ and the negative directcurrent input bus bar 111− can be mutually overlapped and extended untilthe positive direct current power source terminal 151 and the negativedirect current power source terminal 152 of the semiconductor module150. Accordingly, the wiring inductance occurred between both the busbars 111+ and 111− can be reduced by mutual induction effects. As aresult, a serge voltage superposed on the bus bars 111+ and 111− can bereduced in accordance with switching of semiconductor elements 222, 223.

Next, in this embodiment, as shown in FIG. 58, a water cooling flow path160 is arranged within the heat sink 110. Reference numeral 120designates a good heat conducting member of e.g., a silicon systemhaving a high electric insulating property. A columnar projectingportion 1123 is projected from a tip of the leg portion 1122 of thebiasing-holding member 112. The projecting portion 1123 is pressed andfitted into a hole reaching the water cooling flow path 160, which isopened to an upper face of the heat sink 110.

Cooling water of the water cooling flow path 160 can preferably coolthis projecting portion 1123 by increasing the length of a tip of theprojecting portion 1123 projected into the water cooling flow path 160.As a result, the heat resistance between the heat sink 110 and thebiasing-holding member 112 can be reduced. The screw 113 can be alsoomitted in this figure. However, in this case, the feature of mechanicaldetachability is lost.

As shown in FIG. 59, the tip of the projecting portion 1123 may be alsoset to have a length at which the projecting portion 1123 is notprojected into the water cooling flow path 150. In this case, the heatresistance between the heat sink 110 and the biasing-holding member 112is slightly increased in comparison with FIG. 58, but there is anadvantage in which possibility of leakage of cooling water from theclearance of a press-fitting portion can be also excluded. Further, acooling water passage communicated between projecting portions 1123 onboth sides of the biasing-holding member 112 may be also arranged withinthe biasing-holding member 112. In such an arrangement, the coolingwater can flow on both sides of the semiconductor module 150 so thatexcellent cooling effects can be realized.

While the present invention has been shown and described with referenceto the foregoing preferred embodiments, it will be apparent to thoseskilled in the art that changes in form and detail may be made thereinwithout departing from the scope of the invention as defined in theappended claims.

1. A cooled type semiconductor device comprising: a semiconductor moduleincluding metallic heat radiating plates and a semiconductor elementchip interposed between the metallic heat radiating plates; a heat sinkcontacting one of said metallic heat radiating plates at a first side ofthe semiconductor module; and a biasing-holding member having a heatconducting property and pressing another one of said metallic heatradiating plates, wherein the biasing-holding member is provided totransmit heat from a second side of the semiconductor module, which isopposite to the first side, to the heat sink.
 2. A cooled typesemiconductor device according to claim 1, wherein: said biasing-holdingmember is fixed to said heat sink.
 3. A cooled type semiconductor deviceaccording to claim 1, further comprising: a soft heat transfer memberarranged between said biasing-holding member and said heat sink.
 4. Acooled type semiconductor device according to claim 1, furthercomprising: a thin insulating member arranged between saidbiasing-holding member and said heat sink.
 5. A cooled typesemiconductor device according to claim 1, further comprising: a thininsulating member arranged between said biasing-holding member and theone of the metallic heat radiating plates disposed on a side opposed tothe heat sink; another insulating member arranged between said heat sinkand the another one of the metallic heat radiating plates.
 6. A cooledtype semiconductor device according to claim 1, wherein: said heat sinkhas side wall portions adjacent to both sides of said semiconductormodule; said biasing-holding member is formed by a metallic thin plateand both end portions of said biasing-holding member are fixed to saidside wall portions.
 7. A cooled type semiconductor device according toclaim 1, wherein: at least one of said biasing-holding member and saidheat sink has a stopper for regulating a transversal shift of saidsemiconductor module.
 8. A cooled type semiconductor device according toclaim 1, wherein: first one of said biasing-holding member, one of saidmetallic heat radiating plates of said semiconductor module and saidheat sink has concavity portions; second one of said biasing-holdingmember, one of said metallic heat radiating plates of said semiconductormodule and said heat sink has convexity portions fitting to saidconcavity portions.
 9. A cooled type semiconductor device according toclaim 1, wherein: at least one of said biasing-holding member and saidheat sink has a positioning portion for positioning said biasing-holdingmember.
 10. A cooled type semiconductor device according to claim 1,further comprising: a plurality of semiconductor modules each having themetallic heat radiating plates and the semiconductor element chipinterposed between the metallic heat radiating plates, the plurality ofthe semiconductor modules being arranged adjacently to one another andforming three pairs, each of the three pairs constituting an upper armand a lower arm of a three phase inverter circuit; wherein one ofsurfaces of said semiconductor element chip has an area connected to afirst electrode terminal as one of metallic heat radiating plates and anarea connected to a signal terminal, and another one of said surfaces ofthe semiconductor element has an area connected to a second electrodeterminal as another one of the metallic heat radiating plates; and saideach semiconductor modules has a rectangular shape with two sidesparallel to each other, and the first and the second electrode terminalsrespectively projecting from the two sides, and being shifted from eachother in a direction parallel to the two sides.
 11. A cooled typesemiconductor device according to claim 2, wherein: said biasing-holdingmember has a beam portion for pressing and biasing said semiconductormodule, and at least a pair of leg portions projecting from both ends ofsaid beam portion onto the heat sink side.
 12. A cooled typesemiconductor device according to claim 2, further comprising: a coolingfluid passage formed in said heat sink; and an internal cooling passageformed in said biasing-holding member, and communicating with saidcooling fluid passage of said heat sink.
 13. A cooled type semiconductordevice according to claim 11, wherein: each of the leg portions has aportion that has a thickness equal to that of said semiconductor moduleand has a coefficient of thermal expansion approximately equal to anaverage coefficient of thermal expansion of said semiconductor elementchip and said metallic heat radiating plates.
 14. A cooled typesemiconductor device according to claim 11, further comprising: acircuit part disposed on said semiconductor module; wherein saidbiasing-holding member presses said semiconductor module against saidheat sink through the circuit part.
 15. A cooled type semiconductordevice according to claim 11, wherein: said biasing-holding memberpresses said semiconductor module and another semiconductor modulearranged in proximity to said semiconductor module.
 16. A cooled typesemiconductor device according to claim 11, wherein: one of said legportions has a curving shape; an elastic modulus of said semiconductormodule in a thickness direction thereof is larger than that of materialconstituting said biasing-holding member.
 17. A cooled typesemiconductor device according to claim 14, wherein: said another one ofthe metallic heat radiating plates directly contacts a terminal of saidcircuit part.
 18. A cooled type semiconductor device according to claim14, wherein: each of the leg portions has a portion that a thicknessequal to a total thickness of said semiconductor module and said circuitpart, and has a coefficient of thermal expansion approximately equal toan average coefficient of thermal expansion of said metallic heatradiating plates, said semiconductor element chip and said circuit part.19. A cooled type semiconductor device according to claim 14, furthercomprising: a terminal member arranged between said another one of themetallic heat radiating plates and a terminal of said circuit part. 20.A cooled type semiconductor device according to claim 19, wherein: saidsemiconductor module constitutes an inverter circuit; said circuit partis constituted by a smoothing capacitor connected to positive andnegative direct current terminals of said inverter circuit; and saidterminal member is a bus bar that is connected to a direct current powersource.
 21. A cooled type semiconductor device according to claim 20,wherein: said leg portions has a portion that has a thickness equal to atotal thickness of said semiconductor module, the terminal member andsaid circuit part, and has a coefficient of thermal expansionapproximately equal to an average coefficient of thermal expansion ofsaid metallic heat radiating plates, said semiconductor element chip,said terminal member and said circuit part.
 22. A cooled typesemiconductor device, comprising: a semiconductor module includingmetallic heat radiating plates and a semiconductor element chipinterposed between the metallic heat radiating plates; a heat sinkcontacting one of said metallic heat radiating plates; and abiasing-holding member having a heat conducting property and pressinganother one of said metallic heat radiating plates, wherein: both endportions of said biasing-holding member are press-inserted and fixed tosaid heat sink.
 23. A cooled type semiconductor device according toclaim 22, wherein: both the end portions of said biasing-holding memberare exposed to a cooling liquid passage formed within said heat sink.24. A cooled type semiconductor device, comprising: a semiconductormodule including metallic heat radiating plates and a semiconductorelement chip interposed between the metallic heat radiating plates; aheat sink contacting one of said metallic heat radiating plates; and abiasing-holding member having a heat conducting property and pressinganother one of said metallic heat radiating plates, wherein: saidsemiconductor element chip has a main electrode and a control electrodedisposed on a main surface of said semiconductor element chip, and hasanother main electrode disposed on another surface of said semiconductorelement chip; and one of said surfaces is disposed on said heat sinkthrough said metallic heat radiating plate.